Wikipedia is a free online encyclopedia with the aim to allow anyone to edit articles. Wikipedia is the largest and most popular general reference work on the Internet and is ranked among the ten most popular websites. Wikipedia is owned by the nonprofit Wikimedia Foundation.
Wikipedia was launched on January 15, 2001, by Jimmy Wales and Larry Sanger. Sanger coined its name, a portmanteau of wiki and encyclopedia. There was only the English-language version initially, but it quickly developed similar versions in other languages, which differ in content and in editing practices. With 5,454,130 articles, the English Wikipedia is the largest of the more than 290 Wikipedia encyclopedias. Overall, Wikipedia consists of more than 40 million articles in more than 250 different languages and, as of February 2014, it had 18 billion page views and nearly 500 million unique visitors each month.
As of March 2017, Wikipedia has about forty thousand high-quality articles known as Featured Articles and Good Articles that cover vital topics. In 2005, Nature published a peer review comparing 42 science articles from Encyclopaedia Britannica and Wikipedia, and found that Wikipedia’s level of accuracy approached that of Encyclopaedia Britannica.
Wikipedia has been criticized for allegedly exhibiting systemic bias, presenting a mixture of “truths, half truths, and some falsehoods”, and, in controversial topics, being subject to manipulation and spin.
Other collaborative online encyclopedias were attempted before Wikipedia, but none were successful.
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, a web portal company. Its main figures were Jimmy Wales, the CEO of Bomis, 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. Sanger and Wales founded Wikipedia. While Wales is credited with defining the goal of making a publicly editable encyclopedia, Sanger is credited with the strategy of using a wiki to reach that goal. On January 10, 2001, Sanger proposed on the Nupedia mailing list to create a wiki as a “feeder” project for Nupedia.
Wikipedia was 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 first months. Otherwise, there were relatively few rules initially and Wikipedia operated independently of Nupedia. Originally, Bomis intended to make Wikipedia a business for profit.
Wikipedia gained early contributors from Nupedia, Slashdot postings, and web search engine indexing. By August 8, 2001, Wikipedia had over 8,000 articles. On September 25, 2001, Wikipedia had over 13,000 articles. By the end of 2001, it had grown to approximately 20,000 articles and 18 language editions. It had reached 26 language editions by late 2002, 46 by the end of 2003, and 161 by the final days of 2004. Nupedia and Wikipedia coexisted until the former’s servers were taken down permanently in 2003, and its text was incorporated into Wikipedia. The English Wikipedia passed the mark of two million articles on September 9, 2007, making it the largest encyclopedia ever assembled, surpassing even the 1408 Yongle Encyclopedia, which had held the record for almost 600 years.
Citing fears of commercial advertising and lack of control in Wikipedia, users of the Spanish Wikipedia forked from Wikipedia to create the Enciclopedia Libre in February 2002. These moves encouraged Wales to announce that Wikipedia would not display advertisements, and to change Wikipedia’s domain from wikipedia.com to wikipedia.org.
Though the English Wikipedia reached three million articles in August 2009, the growth of the edition, in terms of the numbers of articles and of contributors, appears to have peaked around early 2007. Around 1,800 articles were added daily to the encyclopedia in 2006; by 2013 that average was roughly 800. A team at the Palo Alto Research Center attributed this slowing of growth to the project’s increasing exclusivity and resistance to change. Others suggest that the growth is flattening naturally because articles that could be called “low-hanging fruit”—topics that clearly merit an article—have already been created and built up extensively.