Internet
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This article is
about the public worldwide computer network system. For other uses, see Internet
(disambiguation).
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Internet
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Routing
paths through a portion of the Internet as visualized by the Opte
Project
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General
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Internet
Society (ISOC)
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Domain Name System (DNS)
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Hypertext Transfer Protocol (HTTP)
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Internet Protocol (IP)
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Internet Protocol Suite (TCP/IP)
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Services
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Guides
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This
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Computer
network types by
geographical scope
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The Internet is a global system of interconnected computer networks that use the standard Internet
protocol suite (often
called TCP/IP, although not all applications use TCP) to serve billions of
users worldwide. It is a network
of networks that consists of
millions of private, public, academic, business, and government networks, of
local to global scope, that are linked by a broad array of electronic, wireless
and optical networking technologies. The Internet carries an extensive range of
information resources and services, such as the inter-linked hypertext documents
of the World Wide Web (WWW) and the infrastructure to support email.
Most traditional
communications media including telephone, music, film, and television are
reshaped or redefined by the Internet, giving birth to new services such as Voice over
Internet Protocol (VoIP)
and Internet
Protocol Television (IPTV).
Newspaper, book and other print publishing are adapting to Web site technology,
or are reshaped into blogging and web feeds. The Internet has enabled and
accelerated new forms of human interactions through instant messaging, Internet forums, and social
networking. Online shopping has boomed both for major retail
outlets and small artisans and
traders. Business-to-business and financial
services on the
Internet affect supply chains across entire industries.
The origins of the
Internet reach back to research of the 1960s, commissioned by the United States
government in
collaboration with private commercial interests to build robust,
fault-tolerant, and distributed computer networks. The funding of a new U.S. backbone by
the National
Science Foundation in
the 1980s, as well as private funding for other commercial backbones, led to
worldwide participation in the development of new networking technologies, and
the merger of many networks. The commercialization of what was by the 1990s an
international network resulted in its popularization and incorporation into
virtually every aspect of modern human life. As of 2011, more than 2.2 billion
people – nearly a third of Earth's population — use the services of the Internet.[1]
The Internet has
no centralized governance in either technological implementation or policies
for access and usage; each constituent network sets its own standards. Only the
overreaching definitions of the two principal name spaces in the Internet, the Internet Protocol address space and the Domain Name
System, are directed by a maintainer organization, the Internet Corporation for Assigned Names and Numbers (ICANN). The technical underpinning
and standardization of the core protocols (IPv4 and IPv6) is an activity of the Internet
Engineering Task Force (IETF),
a non-profit organization of loosely affiliated international participants that
anyone may associate with by contributing technical expertise.
Contents
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Terminology
See also: Internet
capitalization conventions
Internet is a short form of the technical term internetwork,[2] the
result of interconnecting computer networks with special gateways or routers.
The Internet is also often referred to as the
Net.
The term the Internet, when referring to
the entire global system of IP networks, has been treated as a proper noun and written with an initial capital letter. In the media and popular
culture, a trend has also developed to regard it as a generic term or common
noun and thus write it as "the internet", without capitalization.
Some guides specify that the word should be capitalized as a noun but not
capitalized as an adjective.[3][4]
The terms Internet and World
Wide Web are often used in
everyday speech without much distinction. However, the Internet and the World Wide Web are not one and the same. The Internet
establishes a global data communications system between computers. In contrast,
the Web is one of the services communicated
via the Internet. It is a collection of interconnected documents (web pages) and other resources, linked by hyperlinks and URLs.[5] In
addition to the Web, the Internet also powers a multitude of other services,
including (among others) email, file transfer, newsgroups, and online games.
Web services can exist apart from the internet, such as on a private intranet.
History
Professor Leonard Kleinrock with the first ARPANET Interface
Message Processors at
UCLA
Main articles: History of the
Internet and History of
the World Wide Web
Research into packet switching started in the early 1960s and packet
switched networks such as Mark I at NPL in the UK,[6] ARPANET, CYCLADES,[7][8] Merit Network,[9] Tymnet, and Telenet, were developed in the late 1960s
and early 1970s using a variety of protocols.
The ARPANET in particular led to the development of protocols for internetworking, where multiple separate
networks could be joined together into a network of networks thanks to the work
of British scientist Donald Davies whose ground-breaking work on Packet Switching was essential to the system.[10]
The first two
nodes of what would become the ARPANET were
interconnected between Leonard Kleinrock's Network Measurement
Center at the UCLA's School of Engineering and Applied Science and Douglas Engelbart's NLS system at SRI International (SRI) in Menlo Park,
California, on 29 October 1969.[11] The third site on the ARPANET was the
Culler-Fried Interactive Mathematics center at the University
of California at Santa Barbara, and the fourth was the University of
Utah Graphics
Department. In an early sign of future growth, there were already fifteen sites
connected to the young ARPANET by the end of 1971.[12][13] These early years were documented in
the 1972 film Computer Networks: The Heralds of Resource Sharing.
Early
international collaborations on ARPANET were sparse. For various political
reasons, European developers were concerned with developing the X.25 networks.[14] Notable exceptions were the Norwegian Seismic Array (NORSAR) in 1972, followed in 1973 by Sweden with satellite
links to the Tanum Earth Station and Peter T. Kirstein's research group in the
UK, initially at the Institute
of Computer Science, London University and later at University
College London.[15]
T3 NSFNET Backbone, c. 1992
In December 1974, RFC 675 – Specification of Internet
Transmission Control Program, by Vinton Cerf, Yogen Dalal, and Carl
Sunshine, used the term internet,
as a shorthand for internetworking;
later RFCs repeat this use, so the word started
out as an adjective rather
than the noun it is
today.[16] Access to the ARPANET was expanded in
1981 when the National
Science Foundation (NSF)
developed the Computer Science Network (CSNET).
In 1982, the Internet
Protocol Suite (TCP/IP)
was standardized and the concept of a world-wide network of fully
interconnected TCP/IP networks called the Internet was introduced.
TCP/IP network
access expanded again in 1986 when the National Science Foundation Network (NSFNET) provided access to supercomputer sites in the United States from
research and education organizations, first at 56 kbit/s and later at 1.5
Mbit/s and 45 Mbit/s.[17] Commercial internet
service providers (ISPs)
began to emerge in the late 1980s and early 1990s. The ARPANET was
decommissioned in 1990. The Internet was commercialized in 1995 when NSFNET was
decommissioned, removing the last restrictions on the use of the Internet to
carry commercial traffic.[18] The Internet started a rapid expansion
to Europe and Australia in the mid to late 1980s[19][20] and to Asia in the late 1980s and
early 1990s.[21]
This NeXT Computer was used by Sir Tim
Berners-Lee at CERN and
became the world's first Web server.
Since the
mid-1990s the Internet has had a tremendous impact on culture and commerce,
including the rise of near instant communication by email, instant messaging, Voice over
Internet Protocol (VoIP)
"phone calls", two-way interactive video calls, and the World Wide Web[22] with its discussion forums, blogs, social networking, and online shopping sites. Increasing amounts of data are
transmitted at higher and higher speeds over fiber optic networks operating at
1-Gbit/s, 10-Gbit/s, or more. The Internet continues to grow, driven by ever
greater amounts of online information and knowledge, commerce, entertainment
and social networking.[23]
During the late
1990s, it was estimated that traffic on the public Internet grew by 100 percent
per year, while the mean annual growth in the number of Internet users was
thought to be between 20% and 50%.[24] This growth is often attributed to the
lack of central administration, which allows organic growth of the network, as
well as the non-proprietary open nature of the Internet protocols, which
encourages vendor interoperability and prevents any one company from exerting
too much control over the network.[25] As of 31 March 2011, the estimated
total number of Internet users was 2.095 billion (30.2% of world
population).[26] It is estimated that in 1993 the
Internet carried only 1% of the information flowing through two-way
telecommunication, by 2000 this figure had grown to 51%, and by 2007 more than
97% of all telecommunicated information was carried over the Internet.[27]
Technology
Protocols
Main article: Internet
protocol suite
As the user data is processed down through the protocol stack,
each layer adds an encapsulation at the sending host. Data is transmitted
"over the wire" at the link level, left to right. The encapsulation
stack procedure is reversed by the receiving host. Intermediate relays remove
and add a new link encapsulation for retransmission, and inspect the IP layer
for routing purposes.
The communications
infrastructure of the Internet consists of its hardware components and a system
of software layers that control various aspects of the architecture. While the
hardware can often be used to
support other software systems, it is the design and the rigorous
standardization process of the software architecture that characterizes the
Internet and provides the foundation for its scalability and success. The
responsibility for the architectural design of the Internet software systems
has been delegated to the Internet
Engineering Task Force (IETF).[28] The IETF conducts standard-setting
work groups, open to any individual, about the various aspects of Internet
architecture. Resulting discussions and final standards are published in a
series of publications, each called a Request for
Comments (RFC), freely
available on the IETF web site. The principal methods of networking that enable
the Internet are contained in specially designated RFCs that constitute the Internet Standards. Other less rigorous
documents are simply informative, experimental, or historical, or document the
best current practices (BCP) when implementing Internet technologies.
The Internet
standards describe a framework known as the Internet
protocol suite. This is a model architecture that divides methods
into a layered system of protocols (RFC 1122, RFC
1123). The layers correspond to the environment or scope in which
their services operate. At the top is the application layer, the space for the
application-specific networking methods used in software applications, e.g., a
web browser program. Below this top layer, the transport layer connects applications on different hosts via the network (e.g., client–server model)
with appropriate data exchange methods. Underlying these layers are the core
networking technologies, consisting of two layers. The internet layer enables computers to identify and
locate each other via Internet Protocol (IP) addresses, and
allows them to connect to one another via intermediate (transit) networks.
Last, at the bottom of the architecture, is a software layer, the link layer, that provides connectivity
between hosts on the same local network link, such as a local area network (LAN)
or a dial-up connection.
The model, also known as TCP/IP, is designed to be independent of
the underlying hardware, which the model therefore does not concern itself with
in any detail. Other models have been developed, such as the Open
Systems Interconnection (OSI)
model, but they are not compatible in the details of description or
implementation; many similarities exist and the TCP/IP protocols are usually
included in the discussion of OSI networking.
The most prominent
component of the Internet model is the Internet Protocol (IP), which provides
addressing systems (IP addresses) for
computers on the Internet. IP enables internetworking and in essence
establishes the Internet itself. IP Version 4 (IPv4) is the initial version used on the first generation of
today's Internet and is still in dominant use. It was designed to address up to
~4.3 billion (109) Internet hosts. However, the explosive
growth of the Internet has led
to IPv4 address
exhaustion, which entered its final stage in 2011,[29] when the global address allocation
pool was exhausted. A new protocol version, IPv6, was developed in the
mid-1990s, which provides vastly
larger addressing capabilities and more efficient routing of Internet traffic. IPv6 is
currently in growing deployment around the world, since Internet
address registries (RIRs)
began to urge all resource managers to plan rapid adoption and conversion.[30]
IPv6 is not
interoperable with IPv4. In essence, it establishes a parallel version of the
Internet not directly accessible with IPv4 software. This means software
upgrades or translator facilities are necessary for networking devices that
need to communicate on both networks. Most modern computer operating systems
already support both versions of the Internet Protocol. Network
infrastructures, however, are still lagging in this development. Aside from the
complex array of physical connections that make up its infrastructure, the
Internet is facilitated by bi- or multi-lateral commercial contracts (e.g., peering agreements), and by technical specifications or protocols that
describe how to exchange data over the network. Indeed, the Internet is defined
by its interconnections and routing policies.
Routing
Internet packet routing is accomplished among various tiers of
Internet Service Providers.
Internet
Service Providers connect
customers (thought of at the "bottom" of the routing hierarchy) to
customers of other ISPs. At the "top" of the routing hierarchy are
ten or so Tier 1 networks, large telecommunication
companies which exchange traffic directly "across" to all other Tier
1 networks via unpaid peering agreements. Tier 2 networks buy Internet transit from other ISP to reach at least some
parties on the global Internet, though they may also engage in unpaid peering
(especially for local partners of a similar size). ISPs can use a single
"upstream" provider for connectivity, or use multihoming to provide protection from problems
with individual links. Internet
exchange points create
physical connections between multiple ISPs, often hosted in buildings owned by
independent third parties.[citation
needed]
Computers and
routers use routing tables to direct IP packets among locally
connected machines. Tables can be constructed manually or automatically via DHCP for an
individual computer or a routing protocol for routers themselves. In
single-homed situations, a default route usually points "up" toward
an ISP providing transit. Higher-level ISPs use the Border Gateway
Protocol to sort out
paths to any given range of
IP addresses across
the complex connections of the global Internet.[citation
needed]
Academic
institutions, large companies, governments, and other organizations can perform
the same role as ISPs, engaging in peering and purchasing transit on behalf of
their internal networks of individual computers. Research networks tend to
interconnect into large subnetworks such as GEANT, GLORIAD, Internet2, and the UK's national
research and education network, JANET. These in turn are built around smaller networks (see
the list of academic computer network organizations).[citation
needed]
Not all computer networks are connected to the Internet. For
example, some classified
United States websites are
only accessible from separate secure networks.[citation
needed]
General
structure
The Internet
structure and its usage characteristics have been studied extensively. It has
been determined that both the Internet IP routing structure and hypertext links
of the World Wide Web are examples of scale-free networks.[31]
Many computer
scientists describe the Internet as a "prime example of a large-scale,
highly engineered, yet highly complex system".[32] The Internet is heterogeneous; for
instance, data transfer
rates and physical
characteristics of connections vary widely. The Internet exhibits "emergent phenomena" that depend on its
large-scale organization. For example, data transfer rates exhibit temporal self-similarity. The principles of the routing and addressing methods for
traffic in the Internet reach back to their origins in the 1960s when the
eventual scale and popularity of the network could not be anticipated. Thus,
the possibility of developing alternative structures is investigated.[33] The Internet structure was found to be
highly robust[34] to random failures and very vulnerable
to high degree attacks.[35]
Governance
Main article: Internet
governance
ICANN headquarters in Marina Del Rey, California, United States
The Internet is a globally distributed network comprising many voluntarily
interconnected autonomous networks. It operates without a central governing
body. However, to maintain interoperability, all technical and policy aspects
of the underlying core infrastructure and the principal name spaces are administered by the Internet Corporation for Assigned Names and Numbers (ICANN), headquartered in Marina del
Rey, California. ICANN is the authority that coordinates the
assignment of unique identifiers for use on the Internet, including domain names, Internet Protocol (IP)
addresses, application port numbers in the transport protocols, and many other
parameters. Globally unified name spaces, in which names and numbers are
uniquely assigned, are essential for the global reach of the Internet. ICANN is
governed by an international board of directors drawn from across the Internet
technical, business, academic, and other non-commercial communities. The
government of the United States continues to have the primary role in approving
changes to the DNS root zone that lies at the heart of the domain
name system.[36] ICANN's role in coordinating the
assignment of unique identifiers distinguishes it as perhaps the only central
coordinating body on the global Internet. On 16 November 2005, the World
Summit on the Information Society, held in Tunis, established the Internet
Governance Forum (IGF)
to discuss Internet-related issues.
Modern
uses
The Internet
allows greater flexibility in working hours and location, especially with the
spread of unmetered high-speed connections. The Internet can be accessed almost
anywhere by numerous means, including through mobile
Internet devices. Mobile phones, datacards, handheld game
consoles and cellular routers allow users to connect to the Internet wirelessly. Within the limitations imposed
by small screens and other limited facilities of such pocket-sized devices, the
services of the Internet, including email and the web, may be available.
Service providers may restrict the services offered and mobile data charges may
be significantly higher than other access methods.
Educational
material at all levels from pre-school to post-doctoral is available from
websites. Examples range from CBeebies, through school and high-school
revision guides, virtual
universities, to access to top-end scholarly literature through the
likes of Google Scholar. For distance
education, help with homework and
other assignments, self-guided learning, whiling away spare time, or just
looking up more detail on an interesting fact, it has never been easier for
people to access educational information at any level from anywhere. The
Internet in general and the World Wide Web in particular are important enablers
of both formal and informal education.
The low cost and
nearly instantaneous sharing of ideas, knowledge, and skills has made collaborative work dramatically easier, with the
help of collaborative
software. Not only can a group cheaply communicate and share ideas
but the wide reach of the Internet allows such groups more easily to form. An
example of this is the free software
movement, which has produced, among other things, Linux, Mozilla Firefox, and OpenOffice.org. Internet chat, whether in
the form of an IRC chat room or channel, via an instant messaging system, or a social networking website, allows colleagues to stay in
touch in a very convenient way when working at their computers during the day.
Messages can be exchanged even more quickly and conveniently than via email.
These systems may allow files to be exchanged, drawings and images to be
shared, or voice and video contact between team members.
Content management systems allow collaborating teams to
work on shared sets of documents simultaneously without accidentally destroying each
other's work. Business and project teams can share calendars as well as
documents and other information. Such collaboration occurs in a wide variety of
areas including scientific research, software development, conference planning,
political activism and creative writing. Social and political collaboration is
also becoming more widespread as both Internet access and computer literacy spread.
The Internet
allows computer users to remotely access other computers and information stores
easily, wherever they may be. They may do this with or without computer security, i.e. authentication and
encryption technologies, depending on the requirements. This is encouraging new
ways of working from home, collaboration and information sharing in many
industries. An accountant sitting at home can audit the
books of a company based in another country, on a server situated in a third country that is
remotely maintained by IT specialists in a fourth. These accounts could have
been created by home-working bookkeepers, in other remote locations, based on
information emailed to them from offices all over the world. Some of these
things were possible before the widespread use of the Internet, but the cost of
private leased lines would have made many of them
infeasible in practice. An office worker away from their desk, perhaps on the
other side of the world on a business trip or a holiday, can access their
emails, access their data using cloud computing, or open a remote desktop session into their office PC using a
secure Virtual Private
Network (VPN)
connection on the Internet. This can give the worker complete access to all of
their normal files and data, including email and other applications, while away
from the office. This concept has been referred to among system
administrators as the
Virtual Private Nightmare,[37] because it extends the secure
perimeter of a corporate network into remote locations and its employees'
homes.
Services
World
Wide Web
Many people use
the terms Internet and World
Wide Web, or just the Web,
interchangeably, but the two terms are not synonymous. The World Wide Web is a global set of documents, images and
other resources, logically interrelated by hyperlinks and referenced with Uniform
Resource Identifiers (URIs).
URIs symbolically identify services, servers, and other databases, and the
documents and resources that they can provide. Hypertext
Transfer Protocol (HTTP)
is the main access protocol of the World Wide Web, but it is only one of the
hundreds of communication protocols used on the Internet. Web services also use HTTP to allow software
systems to communicate in order to share and exchange business logic and data.
World Wide Web
browser software, such as Microsoft's Internet Explorer, Mozilla Firefox, Opera, Apple's Safari,
and Google Chrome, lets users navigate from one
web page to another via hyperlinks embedded in the documents. These documents
may also contain any combination of computer data, including graphics, sounds, text, video, multimedia and interactive content that runs
while the user is interacting with the page. Client-side
software can include
animations, games, office
applications and
scientific demonstrations. Through keyword-driven Internet research using search engines like Yahoo! and Google,
users worldwide have easy, instant access to a vast and diverse amount of
online information. Compared to printed media, books, encyclopedias and
traditional libraries, the World Wide Web has enabled the decentralization of
information on a large scale.
The Web has also
enabled individuals and organizations to publish ideas
and information to a potentially large audience online
at greatly reduced expense and time delay. Publishing a web page, a blog, or
building a website involves little initial cost and many
cost-free services are available. Publishing and maintaining large,
professional web sites with attractive, diverse and up-to-date information is
still a difficult and expensive proposition, however. Many individuals and some
companies and groups use web
logs or blogs, which are
largely used as easily updatable online diaries. Some commercial organizations
encourage staff to
communicate advice in their areas of specialization in the hope that visitors
will be impressed by the expert knowledge and free information, and be
attracted to the corporation as a result. One example of this practice is Microsoft, whose product developers publish their personal blogs in order
to pique the public's interest in their work. Collections of personal web pages
published by large service providers remain popular, and have become
increasingly sophisticated. Whereas operations such as Angelfire and GeoCities have
existed since the early days of the Web, newer offerings from, for example,
Facebook and Twitter currently have large followings. These operations often
brand themselves as social
network services rather
than simply as web page hosts.
Advertising on popular web pages can be lucrative,
and e-commerce or the sale of products and services
directly via the Web continues to grow.
When the Web began
in the 1990s, a typical web page was stored in completed form on a web server,
formatted in HTML, ready to be sent to a user's browser in response to a
request. Over time, the process of creating and serving web pages has become
more automated and more dynamic. Websites are often created using content
management or wiki software
with, initially, very little content. Contributors to these systems, who may be
paid staff, members of a club or other organization or members of the public,
fill underlying databases with content using editing pages designed for that
purpose, while casual visitors view and read this content in its final HTML
form. There may or may not be editorial, approval and security systems built
into the process of taking newly entered content and making it available to the
target visitors.
Communication
Email is an
important communications service available on the Internet. The concept of
sending electronic text messages between parties in a way analogous to mailing
letters or memos predates the creation of the Internet. Pictures, documents and
other files are sent as email attachments. Emails can be cc-ed to
multiple email addresses.
Internet telephony is another common communications
service made possible by the creation of the Internet. VoIP stands
for Voice-over-Internet Protocol,
referring to the protocol that underlies all Internet communication. The idea
began in the early 1990s with walkie-talkie-like voice applications for
personal computers. In recent years many VoIP systems have become as easy to
use and as convenient as a normal telephone. The benefit is that, as the Internet
carries the voice traffic, VoIP can be free or cost much less than a
traditional telephone call, especially over long distances and especially for
those with always-on Internet connections such as cable or ADSL. VoIP is maturing into a competitive alternative to
traditional telephone service. Interoperability between different providers has
improved and the ability to call or receive a call from a traditional telephone
is available. Simple, inexpensive VoIP network adapters are available that eliminate the need for a personal
computer.
Voice quality can
still vary from call to call, but is often equal to and can even exceed that of
traditional calls. Remaining problems for VoIP include emergency
telephone number dialing
and reliability. Currently, a few VoIP providers provide an emergency service,
but it is not universally available. Traditional phones are line-powered and
operate during a power failure; VoIP does not do so without a backup
power source for the
phone equipment and the Internet access devices. VoIP has also become
increasingly popular for gaming applications, as a form of communication
between players. Popular VoIP clients for gaming include Ventriloand Teamspeak. Wii, PlayStation 3, and Xbox 360 also
offer VoIP chat features.
Data
transfer
File sharing is an example of transferring large
amounts of data across the Internet. A computer file can be emailed to customers,
colleagues and friends as an attachment. It can be uploaded to a website or FTP server for easy download by others. It
can be put into a "shared location" or onto a file server for instant use by colleagues. The
load of bulk downloads to many users can be eased by the use of "mirror"
servers or peer-to-peer networks. In any of these cases,
access to the file may be controlled by user authentication, the transit of the file
over the Internet may be obscured by encryption, and money may change hands for
access to the file. The price can be paid by the remote charging of funds from,
for example, a credit card whose details are also passed – usually fully
encrypted – across the Internet. The origin and authenticity of the file
received may be checked by digital signatures or by MD5 or other message digests. These simple
features of the Internet, over a worldwide basis, are changing the production,
sale, and distribution of anything that can be reduced to a computer file for
transmission. This includes all manner of print publications, software
products, news, music, film, video, photography, graphics and the other arts.
This in turn has caused seismic shifts in each of the existing industries that
previously controlled the production and distribution of these products.
Streaming media is the real-time delivery of digital
media for the immediate consumption or enjoyment by end users. Many radio and
television broadcasters provide Internet feeds of their live audio and video
productions. They may also allow time-shift viewing or listening such as
Preview, Classic Clips and Listen Again features. These providers have been
joined by a range of pure Internet "broadcasters" who never had
on-air licenses. This means that an Internet-connected device, such as a
computer or something more specific, can be used to access on-line media in
much the same way as was previously possible only with a television or radio
receiver. The range of available types of content is much wider, from
specialized technical webcasts to
on-demand popular multimedia services. Podcasting is a variation on this theme, where –
usually audio – material is downloaded and played back on a computer or shifted
to a portable media
player to be listened
to on the move. These techniques using simple equipment allow anybody, with
little censorship or licensing control, to broadcast audio-visual material
worldwide.
Digital media
streaming increases the demand for network bandwidth. For example, standard
image quality needs 1 Mbit/s link speed for SD 480p, HD 720p quality requires
2.5 Mbit/s, and the top-of-the-line HDX quality needs 4.5 Mbit/s for 1080p.[38]
Webcams are a
low-cost extension of this phenomenon. While some webcams can give
full-frame-rate video, the picture either is usually small or updates slowly.
Internet users can watch animals around an African waterhole, ships in the Panama Canal, traffic at a local roundabout
or monitor their own premises, live and in real time. Video chat rooms and video
conferencing are also
popular with many uses being found for personal webcams, with and without
two-way sound. YouTube was founded on 15 February 2005 and is now the leading
website for free streaming video with a vast number of users. It uses a flash-based web player to stream and show
video files. Registered users may upload an unlimited amount of video and build
their own personal profile. YouTube claims that its users watch hundreds of
millions, and upload hundreds of thousands of videos daily.[39]
Access
Main article: Internet access
Common methods of Internet access in homes include dial-up, landline broadband (over coaxial cable, fiber optic or copper wires), Wi-Fi, satellite and 3G/4G technology cell phones. Public places to use the
Internet include libraries and Internet cafes, where computers with
Internet connections are available. There are also Internet access points in many public places such as airport
halls and coffee shops, in some cases just for brief use while standing.
Various terms are used, such as "public Internet kiosk", "public
access terminal", and "Web payphone". Many hotels now also have
public terminals, though these are usually fee-based. These terminals are
widely accessed for various usage like ticket booking, bank deposit, online
payment etc. Wi-Fi provides wireless access to computer networks, and therefore
can do so to the Internet itself. Hotspots providing
such access include Wi-Fi cafes, where would-be users need to
bring their own wireless-enabled devices such as a laptop or PDA.
These services may be free to all, free to customers only, or fee-based. A
hotspot need not be limited to a confined location. A whole campus or park, or
even an entire city can be enabled.
Grassroots efforts have led to wireless
community networks. Commercial Wi-Fi services covering large city
areas are in place in London, Vienna, Toronto, San Francisco, Philadelphia, Chicago and Pittsburgh. The Internet can then be
accessed from such places as a park bench.[40] Apart from Wi-Fi, there have been
experiments with proprietary mobile wireless networks like Ricochet,
various high-speed data services over cellular phone networks, and fixed
wireless services. High-end mobile phones such as smartphones in general come with Internet access
through the phone network. Web browsers such as Opera are available on these advanced
handsets, which can also run a wide variety of other Internet software. More
mobile phones have Internet access than PCs, though this is not as widely used.[41] An Internet access provider and
protocol matrix differentiates the methods used to get online.
An Internet
blackout or outage can be caused by local signaling interruptions. Disruptions
of submarine
communications cables may
cause blackouts or slowdowns to large areas, such as in the 2008
submarine cable disruption. Less-developed countries are more
vulnerable due to a small number of high-capacity links. Land cables are also
vulnerable, as in 2011 when a woman digging for scrap metal severed most
connectivity for the nation of Armenia.[42] Internet blackouts affecting almost
entire countries can be achieved by governments as a form of Internet
censorship, as in the blockage of the Internet in Egypt, whereby approximately 93%[43] of networks were without access in 2011
in an attempt to stop mobilization for anti-government
protests.[44]
Users
See also: Global
Internet usage, English on the
Internet, and Unicode
Overall Internet
usage has seen tremendous growth. From 2000 to 2009, the number of Internet
users globally rose from 394 million to 1.858 billion.[48] By 2010, 22 percent of the world's
population had access to computers with 1 billion Google searches
every day, 300 million Internet users reading blogs, and 2 billion videos
viewed daily on YouTube.[49]
The prevalent
language for communication on the Internet has been English. This may be a
result of the origin of the Internet, as well as the language's role as a lingua franca. Early computer systems were
limited to the characters in the American Standard Code for Information Interchange (ASCII), a subset of the Latin alphabet.
After English
(27%), the most requested languages on the World Wide Web are Chinese (23%), Spanish (8%),
Japanese (5%), Portuguese and German (4% each), Arabic, French and Russian (3%
each), and Korean (2%).[50] By region, 42% of the world's Internet users are based in Asia, 24% in Europe, 14%
in North America, 10% in Latin America and the Caribbean taken
together, 6% in Africa, 3% in the Middle East and 1% in Australia/Oceania.[51] The Internet's technologies have
developed enough in recent years, especially in the use of Unicode, that good facilities are available
for development and communication in the world's widely used languages.
However, some glitches such as mojibake (incorrect display of some languages'
characters) still remain.
In an American
study in 2005, the percentage of men using the Internet was very slightly ahead
of the percentage of women, although this difference reversed in those under
30. Men logged on more often, spent more time online, and were more likely to
be broadband users, whereas women tended to make more use of opportunities to
communicate (such as email). Men were more likely to use the Internet to pay
bills, participate in auctions, and for recreation such as downloading music
and videos. Men and women were equally likely to use the Internet for shopping
and banking.[52] More recent studies indicate that in
2008, women significantly outnumbered men on most social networking sites, such
as Facebook and Myspace, although the ratios varied with age.[53] In addition, women watched more
streaming content, whereas men downloaded more.[54] In terms of blogs, men were more
likely to blog in the first place; among those who blog, men were more likely
to have a professional blog, whereas women were more likely to have a personal
blog.[55]
Social
impact
Main article: Sociology of
the Internet
The Internet has
enabled entirely new forms of social interaction, activities, and organizing,
thanks to its basic features such as widespread usability and access. In the
first decade of the 21st century, the first generation is raised with
widespread availability of Internet connectivity, bringing consequences and
concerns in areas such as personal privacy and identity, and distribution of
copyrighted materials. These "digital natives" face a variety of challenges that were not
present for prior generations.
Social
networking and entertainment
See also: Social
networking service#Social impact
Many people use
the World Wide Web to access news, weather and sports reports, to plan and book
vacations and to find out more about their interests. People use chat, messaging and email to make and stay
in touch with friends worldwide, sometimes in the same way as some previously
had pen pals. The Internet has seen a growing
number of Web desktops, where users can access their
files and settings via the Internet.
Social networking websites such as Facebook, Twitter, and MySpace have
created new ways to socialize and interact. Users of these sites are able to
add a wide variety of information to pages, to pursue common interests, and to
connect with others. It is also possible to find existing acquaintances, to
allow communication among existing groups of people. Sites like LinkedIn foster
commercial and business connections. YouTube and Flickr specialize
in users' videos and photographs.
The Internet has
been a major outlet for leisure activity since its inception, with entertaining
social experiments such as MUDs and MOOs being conducted on university servers,
and humor-related Usenetgroups receiving much traffic. Today, many Internet forums have sections devoted to games and
funny videos; short cartoons in the form of Flash movies are also popular. Over 6 million
people use blogs or message boards as a means of communication and for the
sharing of ideas. The pornography and gambling industries have taken advantage
of the World Wide Web, and often provide a significant source of advertising
revenue for other websites.[56] Although many governments have
attempted to restrict both industries' use of the Internet, in general this has
failed to stop their widespread popularity.[57]
Another area of
leisure activity on the Internet is multiplayer gaming.[58] This form of recreation creates
communities, where people of all ages and origins enjoy the fast-paced world of
multiplayer games. These range from MMORPG to first-person
shooters, from role-playing
video games to online gambling. While online gaming has
been around since the 1970s, modern modes of online gaming began with
subscription services such as GameSpy and MPlayer.[59] Non-subscribers were limited to
certain types of game play or certain games. Many people use the Internet to
access and download music, movies and other works for their enjoyment and
relaxation. Free and fee-based services exist for all of these activities,
using centralized servers and distributed peer-to-peer technologies. Some of
these sources exercise more care with respect to the original artists'
copyrights than others.
Internet usage has
been correlated to users' loneliness.[60] Lonely people tend to use the Internet
as an outlet for their feelings and to share their stories with others, such as
in the "I am
lonely will anyone speak to me" thread.
Cybersectarianism is a new organizational form which
involves: "highly dispersed small groups of practitioners that may remain
largely anonymous within the larger social context and operate in relative
secrecy, while still linked remotely to a larger network of believers who share
a set of practices and texts, and often a common devotion to a particular
leader. Overseas supporters provide funding and support; domestic practitioners
distribute tracts, participate in acts of resistance, and share information on
the internal situation with outsiders. Collectively, members and practitioners
of such sects construct viable virtual communities of faith, exchanging
personal testimonies and engaging in collective study via email, on-line chat
rooms and web-based message boards."[61]
Cyberslacking can become a drain on corporate
resources; the average UK employee spent 57 minutes a day surfing the Web while
at work, according to a 2003 study by Peninsula Business Services.[62] Internet
addiction disorder is
excessive computer use that interferes with daily life. Psychologist Nicolas
Carr believe that Internet use has other effects
on individuals, for instance improving skills of scan-reading and
interfering with the deep thinking that leads to true creativity.[63]
Politics
and political revolutions
The Internet has
achieved new relevance as a political tool. The presidential campaign of Howard Dean in 2004 in the United States was
notable for its success in soliciting donation via the Internet. Many political
groups use the Internet to achieve a new method of organizing in order to carry
out their mission, having given rise to Internet activism, most notably practiced
by rebels in the Arab Spring.[64][65]
The New York Times suggested that social media websites such as Facebook and Twitter
helped people organize the political revolutions in Egypt where it helped
certain classes of protesters organize protests, communicate grievances, and
disseminate information.[66]
The potential of
the Internet as a civic tool of communicative power was thoroughly explored by Simon
R. B. Berdal in his
thesis of 2004:
As the globally evolving Internet provides ever new access points
to virtual discourse forums, it also promotes new civic relations and
associations within which communicative power may flow and accumulate. Thus,
traditionally ... national-embedded peripheries get entangled into greater,
international peripheries, with stronger combined powers... The Internet, as a
consequence, changes the topology of the "centre-periphery" model, by
stimulating conventional peripheries to interlink into
"super-periphery" structures, which enclose and "besiege"
several centres at once.[67]
Berdal, therefore,
extends the Habermasian notion of the Public sphere to the Internet, and underlines the
inherent global and civic nature that intervowen Internet technologies provide.
To limit the growing civic potential of the Internet, Berdal also notes how
"self-protective measures" are put in place by those threatened by it:
If we consider China’s attempts to filter "unsuitable
material" from the Internet, most of us would agree that this resembles a
self-protective measure by the system against the growing civic potentials of
the Internet. Nevertheless, both types represent limitations to
"peripheral capacities". Thus, the Chinese government tries to
prevent communicative power to build up and unleash (as the 1989
Tiananmen Square uprising suggests,
the government may find it wise to install "upstream measures"). Even
though limited, the Internet is proving to be an empowering tool also to the
Chinese periphery: Analysts believe that Internet petitions have influenced policy
implementation in favour of the public’s online-articulated will ...[67]
Philanthropy
The spread of
low-cost internet access in developing countries has opened up new
possibilities for peer-to-peer
charities, which allow individuals to contribute small amounts to
charitable projects for other individuals. Websites such as DonorsChoose and GlobalGiving allow small-scale donors to direct
funds to individual projects of their choice.
A popular twist on
internet-based philanthropy is the use of peer-to-peer
lending for charitable
purposes. Kiva pioneered
this concept in 2005, offering the first web-based service to publish
individual loan profiles for funding. Kiva raises funds for local intermediary microfinance organizations which post stories and
updates on behalf of the borrowers. Lenders can contribute as little as $25 to
loans of their choice, and receive their money back as borrowers repay. Kiva
falls short of being a pure peer-to-peer charity, in that loans are disbursed
before being funded by lenders and borrowers do not communicate with lenders
themselves.[68][69]
However, the
recent spread of low cost Internet access in developing
countries has made
genuine international person-to-person philanthropy increasingly feasible. In
2009 the US-based nonprofit Zidishatapped into this trend to offer the
first person-to-person microfinance platform to link lenders and borrowers
across international borders without intermediaries. Members can fund loans for
as little as a dollar, which the borrowers then use to develop business
activities that improve their families' incomes while repaying loans to the
members with interest. Borrowers access the internet via public cybercafes,
donated laptops in village schools, and even smart phones, then create their
own profile pages through which they share photos and information about
themselves and their businesses. As they repay their loans, borrowers continue
to share updates and dialogue with lenders via their profile pages. This direct
web-based connection allows members
themselves to take on many of the communication and recording tasks
traditionally performed by local organizations, bypassing geographic barriers
and dramatically reducing the cost of microfinance services to the
entrepreneurs.[70]
Censorship
Main articles: Internet
censorship and Internet freedom
Some governments,
such as those of Burma, Iran, North Korea, the People's
Republic of China, Saudi Arabia, and the United Arab
Emirates restrict what
people in their countries can access on the Internet, especially political and
religious content. This is accomplished through software that filters domains
and content so that they may not be easily accessed or obtained without
elaborate circumvention.[71]
In Norway,
Denmark, Finland, and Sweden, major Internet service providers have
voluntarily, possibly to avoid such an arrangement being turned into law,
agreed to restrict access to sites listed by authorities. While this list of
forbidden URLs is supposed to contain addresses of only known child pornography
sites, the content of the list is secret.[72] Many countries, including the United
States, have enacted laws against the possession or distribution of certain
material, such as child pornography, via the Internet, but do
not mandate filtering software.
There are many free and commercially available software programs, called content-control
software, with which a user can choose to block offensive websites
on individual computers or networks, in order to limit a child's access to
pornographic materials or depiction of violence.
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