Wikipedia

Wikipedia is a free, multilingual, open content encyclopedia project operated by the non-profit Wikimedia Foundation. Its name is a blend of the words wiki (a technology for creating collaborative websites) and encyclopedia. Launched in 2001 by Jimmy Wales and Larry Sanger it is the largest, fastest-growing and most popular general reference work currently available on the Internet.

As of April 2008, Wikipedia attracts 683 million visitors annually reading over 10 million articles in 253 languages, comprising a combined total of over 1.74 billion words for all Wikipedias. The English Wikipedia edition passed the 2,000,000-article mark on September 9, 2007, and as of May 22, 2008 it had over 2,383,000 articles consisting of over 1,034,000,000 words. Wikipedia's articles have been written collaboratively by volunteers around the world, and nearly all of its articles can be edited by anyone with access to the Internet. Having steadily risen in popularity since its inception, it currently ranks among the top ten most-visited web sites worldwide.

Critics of Wikipedia target its systematic bias and inconsistencies and its policy of favoring consensus over credentials in its editorial process. As a result, contemporary popular icons with relatively low overall significance (TV hosts, pop singers etc.) are often more prominently featured than historical figures with high global importance. Wikipedia's reliability and accuracy are also an issue. Other criticisms are centered on its susceptibility to vandalism and the addition of spurious or unverified information. Scholarly work suggests that vandalism is generally short-lived.

In addition to being an encyclopedic reference, Wikipedia has received major media attention as an online source of breaking news as it is constantly updated. When Time Magazine recognized "You" as its Person of the Year 2006, praising the accelerating success of on-line collaboration and interaction by millions of users around the world, Wikipedia was the first particular "Web 2.0" service mentioned, followed by YouTube and MySpace.

History
Wikipedia began as a complementary project for Nupedia, a free online English-language encyclopedia project whose articles were written by experts and reviewed under a formal process. Nupedia was founded on March 9, 2000, under the ownership of Bomis, Inc, a web portal company. Its main figures were Jimmy Wales, Bomis CEO, and Larry Sanger, editor-in-chief for Nupedia and later Wikipedia. Nupedia was licensed initially under its own Nupedia Open Content License, switching to the GNU Free Documentation License before Wikipedia's founding at the urging of Richard Stallman. Larry Sanger and Jimmy Wales are the founders of Wikipedia. “I can start an article that will consist of one paragraph, and then a real expert will come along and add three paragraphs and clean up my one paragraph," said Larry Sanger of Las Vegas, who founded Wikipedia with Mr. Wales. While Wales is credited with defining the goal of making a publicly editable encyclopedia, Sanger is usually credited with the counter-intuitive strategy of using a wiki to reach that goal. On January 10, 2001, Larry Sanger proposed on the Nupedia mailing list to create a wiki as a "feeder" project for Nupedia. Wikipedia was formally launched on January 15, 2001, as a single English-language edition at www.wikipedia.com, and announced by Sanger on the Nupedia mailing list. Wikipedia's policy of "neutral point-of-view" 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.

Wikipedia gained early contributors from Nupedia, Slashdot postings, and Web 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 closing stages 2004. Nupedia and Wikipedia coexisted until the former's servers went down permanently in 2003, and its text was incorporated into Wikipedia. As of December 2007, English Wikipedia had over 2 million articles, making it the largest encyclopedia ever assembled, eclipsing even the Yongle Encyclopedia (1407), which had held the record for exactly 600 years.

Citing 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. Later that year, Wales announced that Wikipedia would not display advertisements, and its website was moved to wikipedia.org. Various other projects have since forked from Wikipedia for editorial reasons. Wikinfo does not require neutral point of view and allows original research. New Wikipedia-inspired projects — such as Citizendium, Scholarpedia, Amapedia and Google's Knol — 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. 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.

Editing model and community
Almost every article in Wikipedia may be edited anonymously or with a user account, while only registered users may create a new article. The "History" page attached to each article contains every single past revision of the article, though a revision with libelous content, criminal threats or copyright infringements may be removed afterwards. Unlike traditional encyclopedias such as Encyclopædia Britannica, no article in Wikipedia undergoes formal peer-review process and changes to articles are made available immediately. Consequently, Wikipedia "makes no guarantee of validity" of its content. Wikipedia also does not censor itself, and it contains materials that a certain group of people may find objectionable or offensive. For instance, in 2008, Wikipedia rejected an online petition against the inclusion of Muhammad's depictions in English Wikipedia, citing this policy. The presence of politically sensitive materials in Wikipedia had also led China to block the access to the site.

Content in Wikipedia is, however, subject to the law in Florida, United States, where Wikipedia servers are hosted, and several internal policies and guidelines; they need to be on "notable" topics, contain "no original research" and only "verifiable" material and must be written from a "neutral point of view." The project relies on its community members, called Wikipedians, to ensure the articles adhere to those policies and guidelines and to delete or modify those failing to meet them. Deletionism and inclusionism are two editor philosophies on the extent of these modifications and deletions. The vandalism to articles is dealt with by Wikipedians or, more increasingly, by computer programs called bots.

Wikipedia tries to address the problem of systemic bias, and to deal with zealous editors who seek to influence the presentation of an article in a biased way, by insisting on a neutral point of view. The English-language Wikipedia has introduced an assessment scale against which the quality of articles is judged; other editions have also adopted this. Roughly 1,500 articles 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.

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.

, an annual conference for users of Wikipedia and other projects operated by the Wikimedia Foundation.

While they are welcomed by the community, authors new to Wikipedia are encouraged to read policies to help them learn the ways of Wikipedia. Editors in good standing in the community can run for one of many of levels of volunteer stewardship; this begins with "sysop|administrator" and goes up with "steward" and "bureaucrat". Administrators, the largest group of privileged users ( for the English edition on February 23, 2008), have the ability to delete pages, lock articles from being changed in case of vandalism or editorial disputes, and block users from editing.

As Wikipedia grows with an unconventional model of encyclopedia building, "Who writes Wikipedia?" has become one of the questions frequently asked on the project, often with a reference to other Web 2.0 projects such as Digg. Jimmy Wales, the founder of Wikipedia, once argued that only "a community ... a dedicated group of a few hundred volunteers" makes a bulk of contributions to Wikipedia and that the project is therefore "much like any traditional organization". This was later disputed by Aaron Swartz, who noted that several articles he sampled had large portion of their content contributed by a user with low edit count. A 2007 study by researchers from Dartmouth College found that anonymous and infrequent contributors to Wikipedia are as reliable a source of knowledge as those contributors who register with the site. Although some contributors are authorities in their field, Wikipedia requires that even their contributions be supported by published and verifiable sources. The project's preference for consensus over credentials has been labeled "anti-elitism".

While praising many aspects of Wikipedia, historian Roy Rosenzweig noted: "Overall, writing is the Achilles' heel of Wikipedia. Committees rarely write well, and Wikipedia entries often have a choppy quality that results from the stringing together of sentences or paragraphs written by different people."

In 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 were attempts to remove criticism. 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."

Reliability and bias
Wikipedia has been accused of exhibiting systemic bias and inconsistency; critics argue that Wikipedia's open nature and a lack of proper sources for much of the information makes it unreliable. Some commentators suggest that Wikipedia is generally reliable, but that the reliability of any given article is not always clear. Editors of traditional reference works such as the Encyclopædia Britannica have questioned the project's utility and status as an encyclopedia. Many university lecturers discourage students from citing any encyclopedia in academic work, preferring primary sources; some specifically prohibit Wikipedia citations. 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. Technology writer Bill Thompson commented that the debate was possibly "symptomatic of much learning about information which is happening in society today."

Concerns have also been raised regarding the lack of accountability that results from users' anonymity, and that it is vulnerable to vandalism, the insertion of spurious information and similar problems. In one particularly well-publicized incident, false information was introduced into the biography of John Seigenthaler, Sr. and remained undetected for four months. Some critics claim that Wikipedia's open structure makes it an easy target for Internet trolls, advertisers, and those with an agenda to push. The addition of political spin to articles by organizations including the U.S. House of Representatives and special interest groups.

Economist Tyler Cowen writes, "If I had to guess whether Wikipedia or the median refereed journal article on economics was more likely to be true, after a not so long think I would opt for Wikipedia." He comments that many traditional sources of non-fiction suffer from systemic biases. Novel results are over-reported in journal articles, and relevant information is omitted from news reports. But he also cautions that errors are frequently found in Internet sites, and that academics and experts must be vigilant in correcting them.

In February 2007, an article in The Harvard Crimson newspaper reported that some of the professors at Harvard University include Wikipedia in their syllabus, but that there is a split in their perception of using Wikipedia. In June 2007, former president of the American Library Association Michael Gorman condemned Wikipedia, along with Google, 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 either are 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 the academics who cite Wikipedia that: “You cannot say children are intellectually lazy because they are using the Internet when academics are using search engines in their research," she said. "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."

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 editing – but the community has been unable to form a consensus in favor of such changes, partly because they would require a major software overhaul. However 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. 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.

Wikimedia Foundation and Wikia
Wikipedia is funded and operated by the Wikimedia Foundation, a non-profit organization which also operates Wikipedia-related projects such as Wikibooks. In an interview, Jimmy Wales said that the foundation spent $2 million of donor money in 2007 toward site maintenance costs. The foundation shares hosting and bandwidth costs with Wikia, a for-profit company founded by Jimmy Wales and Angela Beesley. The Wikimedia Foundation received some donated office space from Wikia Inc. during the fiscal year ending June 30 2006.

Software and hardware
The operation of Wikipedia depends on MediaWiki, a custom-made, free and open source software|open source wiki software platform written in PHP and built upon the MySQL database. The software incorporates programming features such as a macro language, variables, a transclusion system for Web 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.

Wikipedia currently runs on dedicated computer clusters of GNU/Linux servers, 300 in Florida, 26 in Amsterdam and 23 in Yahoo!'s Korean hosting facility in Seoul. 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 hosting service|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 (software)|Squid cache servers.

Wikipedia receives between 20,000 and 45,000 page requests per second, depending on time of day. Page requests are first passed to a front-end layer of Squid caching servers. 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 for anonymous users 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 is 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. The position that Wikipedia is a merely a hosting service has been successfully used as a defense in court. Wikipedia has 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 are currently incompatible.

The 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 253 language editions of Wikipedia; of these, 16 have over 100,000 articles and 145 have over 1,000 articles.(See List of Wikipedias for the full list.) According to Alexa, the English subdomain (en.wikipedia.org; English Wikipedia) receives approximately 55% of Wikipedia's cumulative traffic, with the remaining split among the other languages (Spanish: 17%, Japanese 4%, German: 4%, Polish: 3%, French: 3%, Portuguese: 2%).As of December 2007, the five largest language editions are (in order of article count) English, German, French, Polish and Japanese Wikipedias.