Wikipedia was the first large scale test of wiki technology for general purpose public knowledge base gathering and distribution. As of early July 2004 the English Wikipedia had more than 335,345 articles (as of August 28, 2004) and thousands of contributors. It is by far the largest wiki system. The second largest wiki is the German Wikipedia with over 132,165 articles.
Wikipedia spread as an umbrella over international wiki systems with its largest underwriters Bomis.com, providing servers and bandwidth for any language of wiki for which contributors were willing to set up a version in their language.
After experimenting with Nupedia, which relied on approved editors for quality control, Wikipedia founder Jimmy Wales concluded that a top-down "cathedral" development model would not allow the project to be successful. Wales sought a method whereby a larger group of users could asynchronously or simultaneously review content. Wiki software, which allows casual users easier access to editing tools, offered Wales an alternative to the problems he saw in the Nupedia model. Wikipedia soon developed a large group of regular users who controled content by reviewing recent changes and individual watch-lists of pages that they wanted to watch for changes.
In a contrast to the Nupedia model, in which edit privileges were difficult to come by, Wikipedia offered edit privileges by default. Administrators revoke edit privileges at their discretion based on policies, and on their opinion of content or contributors.
Wikipedia, more so than other wiki services in early 2004, had become a main source for encyclopedic content redistributed by other sites. While this means that a much greater body of Internet content is freely available, it also means that any errors in Wikipedia are reproduced across the Internet.
Some aspects of wiki systems may be inherently unreliable. In wikis such as Wikipedia with no formal fact-checking process, it can be a matter of luck when explicit plagiarism or inaccurate statements are discovered. While advocates of Wikipedia have stated in news interviews their hope that the project's popularity will attract a large number of concerned users who will find content that doesn't serve the wiki's purpose, verification problems can be independent of the number of users if the percentage of erroneous entries remains proportional among a growing total number of users.
Although experts on a subject may edit a page, they ultimately have no more control over the content of that page than anyone else. Contributors with unique knowledge of unusual subjects may be mistrusted by editors with general knowledge, or to put it less diplomatically, little or no knowledge, who rely on searches of other Internet sites to review new information. Administrators or editors might analyze writing skills or rely on opinions about a contributor to inform decisions when they have no knowledge of the subject of an article, or on a poll of individuals as ill-informed about the subject at hand as they are, themselves.
Assembly of a public knowledge base by voluntary associations can offer easy access to knowledge for future generations. But with a lack of verifiability, and with obscene, opinionated or incorrect entries as on-going features, wikis such as Wikipedia might be self-limiting in their scope. At Wikipedia, fact checking is a constant process undertaken by anyone who chooses to get involved and represents themself as knowledgable.
Wikipedia is readable by anyone with a computer and an Internet connnection but it is not a publically owned or operated organization. Discussions of both policy and content at Wikipedia are open to discussion and debate on mailing lists, wiki pages, and web forums. The forums are largely unmoderated in that contributions are not screened before they are published, except in the case of prohibited contributors. Users who have not contributed to articles are allowed to engage in on-line policy discussions at the discretion of administrators.
More problematic are decisions on when critics of the Wikipedia projects should be allowed to participate in discussions or be excluded. Policies allow administrators to exclude users from on-line policy debates or votes for "behavioural reasons". Administrators maintain that they do not exclude members from discussion for reasons related to a critical policy argument. Debates continue over the best methods for resolving editing conflicts and articulating what behavior - or rhetorical style - is problematic.
One criticism of Wikipedia is that "power users" who spend several hours a day making edits or who use software to quickly review a large number of pages may dominate discussions.
Wikipedia's volunteer administration executes policy with technical interventions, with brief votes open to most users, with a volunteer mediation process and with an arbitration committee process based on public airing of evidence or opinions about various grievances. While Wikipedia offers venues for conflict resolution, they have been criticized by some Wikipedians, with some people feeling that the process is unfair and others feeling that it is too unwieldy to resolve problems in a timely fashion.
Wales operated the project with volunteer assistance for several years on Bomis equipment, and for a year paid an employee to get the project going. In late 2003, the entire project was transferred from Bomis to the Wikimedia Foundation, Inc., a nonprofit organization founded by Wales.
The foundation's three original trustees were joint owners of Bomis.com.  In May 2004, Jimmy Wales, chairman of the Wikimedia Foundation board of directors, announced that he is resigning as CEO of Bomis to more fully reflect that he spends most of his time working for the Wikimedia Foundation. Wales announced in May, 2004 that he envisions himself as eventually being paid to run Wikimedia Foundation.
Elections for the contributor and volunteer positions on the Wikimedia Foundation board were held in June 2004. 
As Wikimedia emerged as a non-profit company with Bomis partners in control, Wales announced Wikipedia's first formal plea for independent financial support in December 2003 with a target set at $20,000. An April 4 Wikipedia announcement indicated Wikipedia had raised that amount, but later in April Wales told Salon that the appeal had received $50,000 in donations. 
Bomis.com is the largest underwriter of Wikipedia, providing building space, bandwidth and technical support.
Wikimedia Foundation's bylaws allow the founding Bomis partners continued control of the board of trustees. Under the bylaws for the Wikimedia Foundation Bomis appointed three of the five members with two elected by Wikipedia contributors. In the absence of elected contributor representatives, the board of the Wikimedia Foundation would fill the positions. Replacements for the Bomis appointees would be elected by the board.
Other SourceWatch Resources
- Sam Williams, "Everyone is an editor", Salon, April 27, 2004.
- The initial plan for a free encyclopedia.
- The history of the first free encyclopedia, GNUPedia. (Spanish)
- Aaron Weiss, "The Unassociated Press", New York Times, February 10, 2005.
- Jim Regan, "Wacky Wikipedia", Christian Science Monitor, February 11, 2005.
- Larry Sanger, "The Early History of Nupedia and Wikipedia: A Memoir", Slashdot, April 18, 2005.
- Larry Sanger, "The Early History of Nupedia and Wikipedia: Part II", Slashdot, April 18, 2005.
- Joanna Glasner , "All the News That's Fit to Wiki", Wired, April 22, 2005. (A story on the challenges of Wikinews).
- Rob O'Neill, "Wikipedia worries", Icon, Sydney Morning Herald, August 27, 2005.
- John Seigenthaler, "A false Wikipedia 'biography'",Yahoo News, November 30, 2005.
- Katharine P, Seeyle, "Rewriting History: Snared in the Web of a Wikipedia Liar", New York Times, December 4, 2005.
- "Wikipedia tightens online rules," BBC, December 6, 2005: "Online encyclopaedia Wikipedia has tightened its submission rules following a complaint."
- Daniel Terdiman, "Is Wikipedia safe from libel liability?", CNET News.com, December 7, 2005.
- Anita Ramasastry, "Is an Online Encyclopedia, Such as Wikipedia, Immune From Libel Suits?: Under Current Law, the Answer Is Most Likely Yes, But that Law Should Change", FindLaw, December 12, 2005.
- Suzanne Goldenberg, "Wikipedia hoaxer apologises", The Guardian', December 13, 2005.
- Jim Giles, "nternet encyclopaedias go head to head: Jimmy Wales' Wikipedia comes close to Britannica in terms of the accuracy of its science entries, a Nature investigation finds", Nature, December 14, 2005.
- "The peer review", Nature, December 15, 2005. ("We chose 50 entries from the websites of Wikipedia and the Encyclopaedia Britannica on subjects that represented a broad range of scientific disciplines ... Each pair of entries was sent to an expert for peer review. The reviewers, who were not told which article was which, were asked to look for three types of inaccuracy: factual errors, critical omissions and misleading statements.')
- Jimmy Wales, "Britannica vs. Wikipedia, origin of feathers, the earliest Europeans, life in the Louisiana wetlands, a resurgent Russian space programme and problems with Pokemon", Nature, December 15, 2005. (This is a podcast file).
- Charles Arthur, "Online, it's us or them", Sydney Morning Herald, December 17, 2005.
- Jonathan Dee, "All the News That’s Fit to Print Out", New York Times, July 1, 2007.