wikipediathefreeencyclopedia

Wikipedia is a multilingual, Web-based free content encyclopedia project. The name is a portmanteau of the words wiki and encyclopedia. Wikipedia is written collaboratively by volunteers, allowing most articles to be changed by almost anyone with access to the Web site. Its main servers are in Tampa, Florida, with additional servers in Amsterdam and Seoul.

Wikipedia was launched as an English language project on January 15, 2001, as a complement to the expert-written and now defunct Nupedia, and is now operated by the non-profit Wikimedia Foundation. It was created by Larry Sanger and Jimmy Wales; Sanger resigned from both Nupedia and Wikipedia on March 1, 2002. Wales has described Wikipedia as "an effort to create and distribute a multi-lingual free encyclopedia of the highest possible quality to every single person on the planet in their own language".

Currently Wikipedia has more than five million articles in many languages, including more than 1.5 million in the English-language version and more than half a million in the German-language version. There are 250 language editions of Wikipedia, and 18 of them have more than 50,000 articles each. The German-language edition has been distributed on DVD-ROM, and there have been proposals for an English DVD or print edition. Since its inception, Wikipedia has steadily risen in popularity, and has spawned several sister projects. According to Alexa, Wikipedia ranks among the top fifteen most visited sites, and many of its pages have been mirrored or forked by other sites, such as Answers.com.

There has been controversy over Wikipedia's reliability and accuracy, with the site receiving criticism for its susceptibility to vandalism, uneven quality and inconsistency, systemic bias, and preference for consensus or popularity over credentials. Information is sometimes unconfirmed and questionable, lacking the proper sources that, in the eyes of most "Wikipedians" (as Wikipedia's contributors call themselves), are necessary for an article to be considered "high quality". However, a 2005 comparison performed by the science journal Nature of sections of Wikipedia and the Encyclopedia Britannica found that the two were close in terms of the accuracy of their articles on the natural sciences. This study was challenged by Encyclopedia Britannica Inc., who described it as "fatally flawed".