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Internet censorship is the control or suppression of what can be accessed, published, or viewed on the Internet. It may be carried out by governments or by private organizations at the behest of government, regulators, or on their own initiative. Individuals and organizations may engage in self-censorship for moral, religious, or business reasons, to conform to societal norms, due to intimidation, or out of fear of legal or other consequences. The extent of Internet censorship varies on a country-to-country basis. While most democratic countries have moderate Internet censorship, other countries go as far as to limit the access of information such as news and suppress discussion among citizens.〔 Internet censorship also occurs in response to or in anticipation of events such as elections, protests, and riots. An example is the increased censorship due to the events of the Arab Spring. Other areas of censorship include copyrights, defamation, harassment, and obscene material. Support for and opposition to Internet censorship also varies. In a 2012 Internet Society survey 71% of respondents agreed that "censorship should exist in some form on the Internet". In the same survey 83% agreed that "access to the Internet should be considered a basic human right" and 86% agreed that "freedom of expression should be guaranteed on the Internet". According to GlobalWebIndex, over 400 million people use virtual private networks to circumvent censorship or for increased level of privacy.〔 ==Overview== Many of the issues associated with Internet censorship are similar to those for offline censorship of more traditional media such as newspapers, magazines, books, music, radio, television, and film. One difference is that national borders are more permeable online: residents of a country that bans certain information can find it on websites hosted outside the country. Thus censors must work to prevent access to information even though they lack physical or legal control over the websites themselves. This in turn requires the use of technical censorship methods that are unique to the Internet, such as site blocking and content filtering.〔 Views about the feasibility and effectiveness of Internet censorship have evolved in parallel with the development of the Internet and censorship technologies: * A 1993 ''Time Magazine'' article quotes computer scientist John Gilmore, one of the founders of the Electronic Frontier Foundation, as saying "The Net interprets censorship as damage and routes around it."〔("First Nation in Cyberspace" ), Philip Elmer-Dewitt, ''Time'', 6 December 1993, No.49〕 * In November 2007, "Father of the Internet" Vint Cerf stated that he sees government control of the Internet failing because the Web is almost entirely privately owned.〔("Cerf sees government control of Internet failing" ), Pedro Fonseca, Reuters, 14 November 2007〕 * A report of research conducted in 2007 and published in 2009 by the Berkman Center for Internet & Society at Harvard University stated that: "We are confident that the (censorship circumvention ) tool developers will for the most part keep ahead of the governments' blocking efforts", but also that "...we believe that less than two percent of all filtered Internet users use circumvention tools".〔(''2007 Circumvention Landscape Report: Methods, Uses, and Tools'' ), Hal Roberts, Ethan Zuckerman, and John Palfrey, Beckman Center for Internet & Society at Harvard University, March 2009〕 * In contrast, a 2011 report by researchers at the Oxford Internet Institute published by UNESCO concludes "... the control of information on the Internet and Web is certainly feasible, and technological advances do not therefore guarantee greater freedom of speech."〔 Blocking and filtering can be based on relatively static blacklists or be determined more dynamically based on a real-time examination of the information being exchanged. Blacklists may be produced manually or automatically and are often not available to non-customers of the blocking software. Blocking or filtering can be done at a centralized national level, at a decentralized sub-national level, or at an institutional level, for example in libraries, universities or Internet cafes.〔 Blocking and filtering may also vary within a country across different ISPs. Countries may filter sensitive content on an ongoing basis and/or introduce temporary filtering during key time periods such as elections. In some cases the censoring authorities may surreptitiously block content to mislead the public into believing that censorship has not been applied. This is achieved by returning a fake "Not Found" error message when an attempt is made to access a blocked web.〔 Unless the censor has total control over all Internet-connected computers, such as in North Korea or Cuba, total censorship of information is very difficult or impossible to achieve due to the underlying distributed technology of the Internet. Pseudonymity and data havens (such as Freenet) protect free speech using technologies that guarantee material cannot be removed and prevents the identification of authors. Technologically savvy users can often find ways to access blocked content. Nevertheless, blocking remains an effective means of limiting access to sensitive information for most users when censors, such as those in China, are able to devote significant resources to building and maintaining a comprehensive censorship system.〔 The term "splinternet" is sometimes used to describe the effects of national firewalls. The verb "rivercrab" colloquially refers to censorship of the Internet, particularly in Asia. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Internet censorship」の詳細全文を読む スポンサード リンク
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