Wikipedia is a free,refSome versions such as the English languageversion contain non-free content./ref web-based multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its name is a portmanteau of the words wiki (a technology for creating collaborative websites, from the Hawaiian word wiki, meaning quick) and encyclopedia. Wikipedia's 13 million articles (2.9 million in the English Wikipedia) have been written collaboratively by volunteers around the world, and almost all of its articles can be edited by anyone who can access the Wikipedia website.refIn some parts of the world, the access to Wikipedia has (or had) been blocked./ref Launched in January 2001 by Jimmy Wales and Larry Sanger,ref name=MiliardWho/ref it is currently the largest and most popular general reference work on the Internet.ref name=AlexaStats/refref name=Tancer Cf. Bill Tancer (Global Manager, Hitwise), , Hitwise: An Experian Company (Blog), March 1, 2007. Retrieved December 18, 2008./refref name=Woodson/refref name=AlexaTop500 /Critics of Wikipedia accuse it of systemic bias and inconsistencies,ref name=SangerElitism / and target its policy of favoring consensus over credentials in its editorial process.ref name=AcademiaAndWikipedia/ref Wikipedia's reliability and accuracy are also an issue.ref name=Who/ref Other criticisms are centered on its susceptibility to vandalism and the addition of spurious or unverified information,ref name=DeathByWikipedia / though scholarly work suggests that vandalism is generally short-lived.ref name=MIT_IBM_study/refref name=CreatingDestroyingAndRestoringValue/refJonathan Dee, of The New York Times,ref name=Dee/ref and Andrew Lih, in the 5th International Symposium on Online Journalism,ref name=Lih/ref have cited the importance of Wikipedia not only as an encyclopedic reference but also as a frequently-updated news resource because of how quickly articles about recent events appear.When Time magazine recognized You as its Person of the Year for 2006, acknowledging the accelerating success of online collaboration and interaction by millions of users around the world, it cited Wikipedia as one of three examples of Web 2.0 services, along with YouTube and MySpace.ref name=Time2006/ref

History

thumb|right|smallWikipedia originally developed from another encyclopedia project, , Wikipedia (January 21, 2007)/ref was codified in its initial months, and was similar to Nupedia's earlier nonbiased policy. Otherwise, there were relatively few rules initially and Wikipedia operated independently of Nupedia.ref name=SangerMemoir/thumb|left|smallGraph of the article count for the English Wikipedia, from January 10, 2001, to September 9, 2007 /smallWikipedia gained early contributors from Nupedia, Slashdot postings, and search engine indexing. It grew to approximately 20,000 articles, and 18 language editions, by the end of 2001. By late 2002 it had reached 26 language editions, 46 by the end of 2003, and 161 by the final days of 2004.ref/ref Nupedia and Wikipedia coexisted until the former's servers went down permanently in 2003, and its text was incorporated into Wikipedia. English Wikipedia passed the 2 million-article mark on September 9, 2007, making it the largest encyclopedia ever assembled, eclipsing even the Yongle Encyclopedia (1407), which had held the record for exactly 600nbsp;years.ref name=EB_encyclopedia/refCiting fears of commercial advertising and lack of control in a perceived English-centric Wikipedia, users of the Spanish Wikipedia forked from Wikipedia to create the Enciclopedia Libre in February 2002.ref/ref Later that year, Wales announced that Wikipedia would not display advertisements, and its website was moved to wikipedia.org.ref name=Shirky/ref Various other projects have since forked from Wikipedia for editorial reasons. Wikinfo does not require a neutral point of view and allows original research. New Wikipedia-inspired projectsnbsp; such as Citizendium, Scholarpedia, Conservapedia, and Google's Knolnbsp; have been started to address perceived limitations of Wikipedia, such as its policies on peer review, original research, and commercial advertising.The Wikimedia Foundation was created from Wikipedia and Nupedia on June 20, 2003.refJimmy Wales: , June 20, 2003, Wikipedia-l@wikipedia.org/ref It applied to the United States Patent and Trademark Office to trademark Wikipedia on September 17, 2004. The mark was granted registration status on January 10, 2006. Trademark protection was accorded by Japan on December 16, 2004, and in the European Union on January 20, 2005. Technically a service mark, the scope of the mark is for: Provision of information in the field of general encyclopedic knowledge via the Internet. There are plans to license the use of the Wikipedia trademark for some products, such as books or DVDs.ref/ref

Nature of Wikipedia

Editing model

thumb|smallIn April 2009, . In Communications of the ACM, August 2008, Vol 51, No 8, Pages 68 - 73. DOI:10.1145/1378704.1378720. Quote: Most new articles are created shortly after a corresponding reference to them is entered into the system. See also: Inflationary hypothesis of Wikipedia growth/ref

Reliability and bias

Wikipedia has been accused of exhibiting systemic bias and inconsistency;ref name=Who / critics argue that Wikipedia's open nature and a lack of proper sources for much of the information makes it unreliable.ref/ref Some commentators suggest that Wikipedia is generally reliable, but that the reliability of any given article is not always clear.ref name=AcademiaAndWikipedia / Editors of traditional reference works such as the Encyclopædia Britannica have questioned the project's utility and status as an encyclopedia.ref name=McHenry_2004Robert McHenry, , Tech Central Station, November 15, 2004./ref Many university lecturers discourage students from citing any encyclopedia in academic work, preferring primary sources;ref name=WideWorldOfWikipedia/ref some specifically prohibit Wikipedia citations.ref/ref Co-founder Jimmy Wales stresses that encyclopedias of any type are not usually appropriate as primary sources, and should not be relied upon as authoritative.ref name=AWorkInProgress/refthumb|small , The Harvard Crimson, Monday, February 26, 2007./ref In June 2007, former president of the American Library Association Michael Gorman condemned Wikipedia, along with Google,ref name=stothartChloe Stothart, ,The Times Higher Education Supplement, 2007, 1799 (June 22), page 2/ref stating that academics who endorse the use of Wikipedia are the intellectual equivalent of a dietitian who recommends a steady diet of Big Macs with everything. He also said that a generation of intellectual sluggards incapable of moving beyond the Internet was being produced at universities. He complains that the web-based sources are discouraging students from learning from the more rare texts which are either found only on paper or are on subscription-only web sites. In the same article Jenny Fry (a research fellow at the Oxford Internet Institute) commented on academics who cite Wikipedia, saying that: You cannot say children are intellectually lazy because they are using the Internet when academics are using search engines in their research. The difference is that they have more experience of being critical about what is retrieved and whether it is authoritative. Children need to be told how to use the Internet in a critical and appropriate way.ref name=stothart /!--Speaking at a conference in Pennsylvania, Wales said he receives about ten e-mails weekly from students saying they got failing grades on papers because they cited Wikipedia. According to The Sunday Times of London, Wales told the students they got what they deserved. For God's sake, you're in college; don't cite the encyclopedia, he said.refJimmy Wales, Biography Resource Center Online. (Gale, 2006)/refSo what First we need some paragraph discussing the reliance of Wikipedia in school. -- Taku--There have been efforts within the Wikipedia community to improve the reliability of Wikipedia. The English-language Wikipedia has introduced an assessment scale against which the quality of articles is judged;ref/ref other editions have also adopted this. Roughly 2500 articles in English have passed a rigorous set of criteria to reach the highest rank, featured article status; such articles are intended to provide thorough, well-written coverage of their topic, supported by many references to peer-reviewed publications.ref/ref In order to improve reliability, some editors have called for stable versions of articles, or articles that have been reviewed by the community and locked from further editingbut the community has been unable to form a consensus in favor of such changes, partly because they would require a major software overhaul.ref/refref/ref A similar system is being tested on the German Wikipedia, and there is an expectation that some form of that system will make its way onto the English version at some future time.ref/refref/ref Software created by Luca de Alfaro and colleagues at the University of California, Santa Cruz is now being tested that will assign trust ratings to individual Wikipedia contributors, with the intention that eventually only edits made by those who have established themselves as trusted editors will be made immediately visible.ref/ref

Wikipedia community

The community of editors has a power structure.ref name=iTWireJune18-2006/refref/refWikipedia's community has also been described as cult-like,ref/ref although not always with entirely negative connotations,ref/ref and criticized for failing to accommodate inexperienced users.ref/ref!--While they are welcomed by the community,ref name=TheNewYorker/ref authors new to Wikipedia are encouraged to read policies to help them learn the ways of Wikipedia.ref name=Torsten_Kleinz /-- Editors in good standing in the community can run for one of many levels of volunteer stewardship; this begins with administrator,ref name=David_Mehegan/ref a group of privileged users who have the ability to delete pages, lock articles from being changed in case of vandalism or editorial disputes, and block users from editing. Despite the name, administrators do not enjoy any special privilege in decision-making and are prohibited from using their powers to settle content disputes. The roles of administrators, often described as janitorial, are mostly limited to making edits that have project-wide effects and thus are disallowed to ordinary editors in order to minimize disruption, as well as banning users from making disruptive edits such as vandalism.!--From the beginning, the role of founder Jimmy Wales, within the Wikipedia community, has been unclear, while co-founder Larry Sanger in the early days had served as an editor-in-chief. --thumb|right|small , Kuro5hin, December 31, 2004./refIn August 2007, a website developed by computer science graduate student Virgil Griffith named WikiScanner made its public debut. WikiScanner traces the source of millions of changes made to Wikipedia by editors who are not logged in, which reveals that many of these edits come from corporations or sovereign government agencies about articles related to them, their personnel or their work, and are attempts to remove criticism.ref name=Seeing Corporate Fingerprints/ref!-- Wales called WikiScanner a very clever idea, and said that he was considering some changes to Wikipedia to help visitors better understand what information is recorded about them. When someone clicks on 'edit,' it would be interesting if we could say, 'Hi, thank you for editing. We see you're logged in from The New York Times. Keep in mind that we know that, and it's public information', he said. That might make them stop and think.ref name=Seeing Corporate Fingerprints/--In a 2003 study of Wikipedia as a community, economics Ph.D. student Andrea Ciffolilli argued that the low transaction costs of participating in wiki software create a catalyst for collaborative development, and that a creative construction approach encourages participation.refAndrea Ciffolilli, , First Monday December 2003./ref In his 2008 book, The Future of the Internet and How to Stop It, Jonathan Zittrain of the Oxford Internet Institute and Harvard Law Schools Berkman Center for Internet Society cites Wikipedia's success as a case study in how open collaboration has fostered innovation on the web.ref /ref A 2008 study found that Wikipedians were less agreeable and open, though more conscientious, than non-Wikipedia users.refYair AmichaiHamburger, Naama Lamdan, Rinat Madiel, Tsahi Hayat ''CyberPsychology Behavior'' December 1, 2008, 11(6): 679-681. doi:10.1089/cpb.2007.0225/refref/ref The Wikipedia Signpost is the community newspaper on the English Wikipedia,ref/ref and was founded by Michael Snow, an administrator and the current chair of the Wikimedia Foundation board of trustees.ref/ref It covers news and events from the site, as well as major events from sister projects, such as Wikimedia Commons.ref/ref

Operation

Wikimedia Foundation and the Wikimedia chapters

thumb|small Wikipedia is hosted and funded by the Wikimedia Foundation, a non-profit organization which also operates Wikipedia-related projects such as Wikibooks. The Wikimedia chapters, local associations of Wikipedians, also participate in the promotion, the development, and the funding of the project.

Software and hardware

The operation of Wikipedia depends on MediaWiki, a custom-made, free and open source wiki software platform written in PHP and built upon the MySQL database.ref/ref The software incorporates programming features such as a macro language, variables, a transclusion system for templates, and URL redirection. MediaWiki is licensed under the GNU General Public License and used by all Wikimedia projects, as well as many other wiki projects. Originally, Wikipedia ran on UseModWiki written in Perl by Clifford Adams (Phase I), which initially required CamelCase for article hyperlinks; the present double bracket style was incorporated later. Starting in January 2002 (Phase II), Wikipedia began running on a PHP wiki engine with a MySQL database; this software was custom-made for Wikipedia by Magnus Manske. The Phase II software was repeatedly modified to accommodate the exponentially increasing demand. In July 2002 (Phase III), Wikipedia shifted to the third-generation software, MediaWiki, originally written by Lee Daniel Crocker.Several MediaWiki extensions are installedref/ref to extend the functionality of MediaWiki software.In April 2005 a Lucene extensionref/refref/ref was added to MediaWiki's built-in search and Wikipedia switched from MySQL to Lucene for searching. Currently Lucene Search 2,ref/ref which is written in the Java and based on Lucene library 2.0,ref/ref is used.meta:Server layout diagrams|server layout diagrams on Meta-Wiki./smallWikipedia currently runs on dedicated clusters of Linux servers (mainly Ubuntu),ref/refref/ref with a few OpenSolaris machines for ZFS. As of February 2008, there were 300 in Florida, 26 in Amsterdam, and 23 in Yahoo!'s Korean hosting facility in Seoul.ref name=servers/ref Wikipedia employed a single server until 2004, when the server setup was expanded into a distributed multitier architecture. In January 2005, the project ran on 39 dedicated servers located in Florida. This configuration included a single master database server running MySQL, multiple slave database servers, 21 web servers running the Apache HTTP Server, and seven Squid cache servers.Wikipedia receives between 25,000 and 60,000 page requests per second, depending on time of day.refMonthly request statistics, Wikimedia. Retrieved on 2008-10-31./ref Page requests are first passed to a front-end layer of Squid caching servers.ref/ref Requests that cannot be served from the Squid cache are sent to load-balancing servers running the Linux Virtual Server software, which in turn pass the request to one of the Apache web servers for page rendering from the database. The web servers deliver pages as requested, performing page rendering for all the language editions of Wikipedia. To increase speed further, rendered pages are cached in a distributed memory cache until invalidated, allowing page rendering to be skipped entirely for most common page accesses. Two larger clusters in the Netherlands and Korea now handle much of Wikipedia's traffic load.

License and language editions

All text in Wikipedia was covered by GNU Free Documentation License (GFDL), a copyleft license permitting the redistribution, creation of derivative works, and commercial use of content while authors retain copyright of their work,ref/ref up until June 2009, when the site switched to Creative Commons Attribution-ShareAlike (CC-by-SA) 3.0.ref/ref Wikipedia had been working on the switch to Creative Commons licenses because the GFDL, initially designed for software manuals, is not suitable for online reference works and because the two licenses were incompatible.ref/ref In response to the Wikimedia Foundation's request, in November 2008, the Free Software Foundation (FSF) released a new version of GFDL designed specifically to allow Wikipedia to by August 1, 2009. Wikipedia and its sister projects held a community-wide referendum to decide whether or not to make the license switch.ref/ref The referendum took place from April 9 to 30.ref/ref The results were 75.8% Yes, 10.5% No, and 13.7% No opinion.ref name=voteresulthttp://meta.wikimedia.org/wiki/Licensing_update/Result/ref In consequence of the referendum, the Wikimedia Board of Trustees voted to change to the Creative Commons license, effective June 15, 2009.ref name=voteresult/ The position that Wikipedia is merely a hosting service has been successfully used as a defense in court.ref/refref/refthumb|right|smallPercentage of all Wikipedia articles in English and top ten largest language editions . As of July 2007, less than 23% of Wikipedia articles are in English./smallThe handling of media files (e.g., image files) varies across language editions. Some language editions, such as the English Wikipedia, include non-free image files under fair use doctrine, while the others have opted not to. This is in part because of the difference in copyright laws between countries; for example, the notion of fair use does not exist in Japanese copyright law. Media files covered by free content licenses (e.g., Creative Commons' cc-by-sa) are shared across language editions via Wikimedia Commons repository, a project operated by the Wikimedia Foundation.There are currently 262nbsp;language editions of Wikipedia; of these, 24 have over 100,000nbsp;articles and 81 have over 1,000nbsp;articles.ref name=ListOfWikipedias/ref According to Alexa, the English subdomain (en.wikipedia.org; English Wikipedia) receives approximately 52% of Wikipedia's cumulative traffic, with the remaining split among the other languages (Spanish: 19%, French: 5%, Polish: 3%, German: 3%, Japanese: 3%, Portuguese: 2%).ref name=AlexaStats / As of July 2008, the five largest language editions are (in order of article count) English, German, French, Polish, and Japanese Wikipedias.ref/refSince Wikipedia is web-based and therefore worldwide, contributors of a same language edition may use different dialects or may come from different countries (as is the case for the English edition). These differences may lead to some conflicts over spelling differences, (e.g. color vs. colour)ref/ref or points of view.ref/refThough the various language editions are held to global policies such as neutral point of view, they diverge on some points of policy and practice, most notably on whether images that are not licensed freely may be used under a claim of fair use.ref/refref/refref/ref//meta.wikimedia.org/wiki/Edits_by_project_and_country_of_origin |title=Edits by project and country of origin |date=2006-09-04 |accessdate=2007-10-25 /ref/smallJimmy Wales has described Wikipedia as an effort to create and distribute a free encyclopedia of the highest possible quality to every single person on the planet in their own language.refJimmy Wales, , March 8, 2005, Wikipedia-l@wikimedia.org/ref Though each language edition functions more or less independently, some efforts are made to supervise them all. They are coordinated in part by Meta-Wiki, the Wikimedia Foundation's wiki devoted to maintaining all of its projects (Wikipedia and others).ref/ref For instance, Meta-Wiki provides important statistics on all language editions of Wikipedia,ref/ref and it maintains a list of articles every Wikipedia should have.ref/ref The list concerns basic content by subject: biography, history, geography, society, culture, science, technology, foodstuffs, and mathematics. As for the rest, it is not rare for articles strongly related to a particular language not to have counterparts in another edition. For example, articles about small towns in the United States might only be available in English.Translated articles represent only a small portion of articles in most editions, in part because automated translation of articles is disallowed.ref/ref Articles available in more than one language may offer InterWiki links, which link to the counterpart articles in other editions.Several language versions have published a selection of Wikipedia articles on an optical disk version. An English version, 2006 Wikipedia CD Selection, contained about 2,000 articles. Another English versionref Wikipedia on DVD. Linterweb. Retrieved June 1, 2007./ref developed by Linterweb contains 1988 + articles.ref . Linterweb. Accessed June 1, 2007. Linterweb is authorized to make a commercial use of the Wikipedia trademark restricted to the selling of the Encyclopedia CDs and DVDs./refref . Wikipedia on DVD. Linterweb. Accessed June 1, 2007. The DVD or CD-ROM version 0.5 was commercially available for purchase./ref The Polish version contains nearly 240,000 articles.ref/ref There are also a few German versions.ref/ref

Cultural significance

!-- Every single cultural, media or Internet reference to Wikipedia does not need to be mentioned here and differentiation between what constitutes a matter of significance and what is run-of-the-mill is important when adding content here. --In addition to logistic growth in the number of its articles,ref/ref Wikipedia has steadily gained status as a general reference website since its inception in 2001.ref/ref According to Alexa and comScore, Wikipedia is among the ten most visited websites worldwide.ref name=AlexaTop500/refref/ref Of the top ten, Wikipedia is the only non-profit website. The growth of Wikipedia has been fueled by its dominant position in Google search results;ref/ref about 50% of search engine traffic to Wikipedia comes from Google,ref/ref a good portion of which is related to academic research.ref/ref In April 2007 the Pew Internet and American Life project found that one third of US Internet users consulted Wikipedia.ref/ref In October 2006, the site was estimated to have a hypothetical market value of $580nbsp;million if it ran advertisements.refcite web|url=http://www.watchmojo.com/web/blog/p=626|title=What is Wikipedia.org's Valuation|first=Ashkan|last=Karbasfrooshan|date=2006-10-26|accessdate=2007-12-01/refWikipedia's content has also been used in academic studies, books, conferences, and court cases.ref/refref/refref/ref The Parliament of Canada's website refers to Wikipedia's article on same-sex marriage in the related links section of its further reading list for the Civil Marriage Act.ref , LEGISINFO (March 28, 2005)/ref The encyclopedia's assertions are increasingly used as a source by organizations such as the U.S. Federal Courts and the World Intellectual Property Organizationref name=WP_court_source (the name World Intellectual Property Office should however read World Intellectual Property Organization in this source)/refnbsp; though mainly for supporting information rather than information decisive to a case.ref/ref Content appearing on Wikipedia has also been cited as a source and referenced in some U.S. intelligence agency reports.ref/ref In December 2008, the scientific journal RNA Biology launched a new section for descriptions of families of RNA molecules and requires authors who contribute to the section to also submit a draft article on the RNA family for publication in Wikipedia.ref/refthumb|small , San Antonio Express-News, January 9, 2007./refref , Honolulu Star-Bulletin, January 13, 2007./refIn July 2007, Wikipedia was the focus of a 30-minute documentary on BBC Radio 4ref/ref which argued that, with increased usage and awareness, the number of references to Wikipedia in popular culture is such that the term is one of a select band of 21st-century nouns that are so familiar (Google, Facebook, YouTube) that they no longer need explanation and are on a par with such 20th-century terms as Hoovering or Coke. Many parody Wikipedia's openness, with characters vandalizing or modifying the online encyclopedia project's articles. Notably, comedian Stephen Colbert has parodied or referenced Wikipedia on numerous episodes of his show The Colbert Report and coined the related term wikiality.ref name=wikiality /

The site has created an impact upon several forms of media. Some media sources satirize Wikipedia's susceptibility to inserted inaccuracies, such as a front-page article in The Onion in July 2006 with the title Wikipedia Celebrates 750 Years of American Independence.ref/ref Others may draw upon Wikipedia's statement that anyone can edit, such as The Negotiation, an episode of The Office, where character Michael Scott said that Wikipedia is the best thing ever. Anyone in the world can write anything they want about any subject, so you know you are getting the best possible information. A select few parody Wikipedia's policies, such as the xkcd strip named Wikipedian Protester.

thumb|left|smallAn Dutch filmmaker IJsbrand van Veelen premiered his 45-minute television documentary The Truth According to Wikipedia in April, 2008.refcite web|url=http://www.techcrunch.com/2008/04/08/the-truth-according-to-wikipedia/|title=The Truth According to Wikipedia|last=Schonfeld|first=Erick|date=April 8, 2008|publisher=TechCruch.com|accessdate=2009-05-30/ref Another documentary film about Wikipedia, entitled The Wikipedia Story, is scheduled for a 2009 release. Shot on several continents, the film will cover the history of Wikipedia and feature interviews with Wikipedia editors around the world.ref/refref/ref

On September 28, 2007, Italian politician Franco Grillini raised a parliamentary question with the Minister of Cultural Resources and Activities about the necessity of freedom of panorama. He said that the lack of such freedom forced Wikipedia, the seventh most consulted website to forbid all images of modern Italian buildings and art, and claimed this was hugely damaging to tourist revenues.ref/ref

thumb|small On September 16, 2007, The Washington Post reported that Wikipedia had become a focal point in the 2008 U.S. election campaign, saying, Type a candidate's name into Google, and among the first results is a Wikipedia page, making those entries arguably as important as any ad in defining a candidate. Already, the presidential entries are being edited, dissected and debated countless times each day.refcite news|url=http://www.washingtonpost.com/wp-dyn/content/article/2007/09/16/AR2007091601699_pf.html|title=On Wikipedia, Debating 2008 Hopefuls' Every Facet|author=Jose Antonio Vargas|publisher=The Washington Post|date=2007-09-17|accessdate=2008-12-26/ref An October 2007 Reuters article, entitled Wikipedia page the latest status symbol, reported the recent phenomenon of how having a Wikipedia article vindicates one's notability.refcite news|url=http://www.reuters.com/article/domesticNews/idUSN2232893820071022sp=true|title=Wikipedia page the latest status symbol|author=Jennifer Ablan|publisher=Reuters|date=2007-10-22|accessdate=2007-10-24/ref

Wikipedia won two major awards in May 2004.refTrophy Box, Meta-Wiki (March 28, 2005)./ref The first was a Golden Nica for Digital Communities of the annual Prix Ars Electronica contest; this came with a 10,000 (£6,588; $12,700) grant and an invitation to present at the PAE Cyberarts Festival in Austria later that year. The second was a Judges' Webby Award for the community category.ref/ref Wikipedia was also nominated for a Best Practices Webby. On January 26, 2007, Wikipedia was also awarded the fourth highest brand ranking by the readers of brandchannel.com, receiving 15% of the votes in answer to the question Which brand had the most impact on our lives in 2006ref/ref

In September 2008, Wikipedia received Quadriga A Mission of Enlightenment award of Werkstatt Deutschland along with Boris Tadi, Eckart Höfling, and Peter Gabriel. The award was presented to Jimmy Wales by David Weinberger.ref/ref

Related projects

A number of interactive multimedia encyclopedias incorporating entries written by the public existed long before Wikipedia was founded. The first of these was the 1986 BBC Domesday Project, which included text (entered on BBC Micro computers) and photographs from over 1nbsp;million contributors in the UK, and covering the geography, art, and culture of the UK. This was the first interactive multimedia encyclopedia (and was also the first major multimedia document connected through internal links), with the majority of articles being accessible through an interactive map of the UK. The user-interface and part of the content of the Domesday Project have now been emulated on a website.ref name=Domesday Project and data from the Community Disc (contributions from the general public) -- most articles can be accessed using the interactive map/ref One of the most successful early online encyclopedias incorporating entries by the public was h2g2, which was created by Douglas Adams and is run by the BBC. The h2g2 encyclopedia was relatively light-hearted, focusing on articles which were both witty and informative. Both of these projects had similarities with Wikipedia, but neither gave full editorial freedom to public users. A similar non-wiki project, the GNUPedia project, co-existed with Nupedia early in its history; however, it has been retired and its creator, free software figure Richard Stallman, has lent his support to Wikipedia.ref name=stallman1999 /

Wikipedia has also spawned several sister projects, which are also run by the Wikimedia Foundation. The first, In Memoriam: September!--Do not reformat this date, it is quoted-- 11 Wiki,ref/ref created in October 2002,ref In Memoriam: September 11 wiki (October 28, 2002),/ref detailed the September 11 attacks; this project was closed in October 2006. Wiktionary, a dictionary project, was launched in December 2002;ref , December 12, 2002. Retrieved on 2007-02-02./ref Wikiquote, a collection of quotations, a week after Wikimedia launched, and Wikibooks, a collection of collaboratively written free books. Wikimedia has since started a number of other projects, including Wikiversity, a project for the creation of free learning materials and the provision of online learning activities.ref name=OurProjects , Wikimedia Foundation. Retrieved on 2007-01-24/ref None of those sister projects, however, have come to meet the success of Wikipedia.

Some subsets of Wikipedia's information have been developed, often with additional review for specific purposes.For example, the Wikipedia series of CDs/DVDs, produced by Wikipedians and SOS Children , is a free, hand-checked, non-commercial selection from Wikipedia, targeted around the UK National Curriculum and intended to be useful for much of the English speaking world. and is about the size of a twenty volume encyclopaedia.

Other websites centered on collaborative knowledge base development have drawn inspiration from or inspired Wikipedia. Some, such as Susning.nu, Enciclopedia Libre, and WikiZnanie likewise employ no formal review process, whereas others use more traditional peer review, such as Encyclopedia of Life, Stanford Encyclopedia of Philosophy, Scholarpedia, h2g2, and Everything2. Citizendium, an online encyclopedia, was started by Wikipedia co-founder Larry Sanger in an attempt to create an expert-friendly Wikipedia.ref name=defactoleadercite news|first=Holden|last=Frith|url=http://technology.timesonline.co.uk/tol/news/tech_and_web/the_web/article1571519.ece|title=Wikipedia founder launches rival online encyclopedia|publisher=The Times|date=March 26, 2007,|accessdate=2007-06-27|quote=smallWikipedia's de facto leader, Jimmy Wales, stood by the site's format.nbsp; Holden Frith./small/refref name=Orlowski18smallnbsp; Andrew Orlowski./small/refref name=JayLyman/ref