Wikipedia is a multilingual, web-based, free encyclopedia based on a model of openly editable content. It is the largest and most popular general reference work on the Internet,[3][4][5] and is one of the most popular websites by Alexa rank.[6] It is owned and supported by the Wikimedia Foundation, a non-profit organization which operates on money it receives from donors.[7][8][9]

 

Wikipedia was launched on January 15, 2001, by Jimmy Wales and Larry Sanger.[10] Sanger coined its name,[11][12] as a portmanteau of wiki[notes 3] and "encyclopedia". Initially an English-language encyclopedia, versions in other languages were quickly developed. With 5,717,503 articles,[notes 4] the English Wikipedia is the largest of the more than 290 Wikipedia encyclopedias. Overall, Wikipedia comprises more than 40 million articles in 301 different languages[14] and had 18 billion page views and nearly 500 million unique visitors each month as of February 2014.[15]

In 2005, Nature published a peer review comparing 42 science articles from Encyclopædia Britannica and Wikipedia and found that Wikipedia's level of accuracy approached that of Encyclopædia Britannica.[16] Time magazine stated that the open-door policy of allowing anyone to edit had made Wikipedia the biggest and possibly the best encyclopedia in the world and it was testament to the vision of Jimmy Wales.

Fair use materials and special requirements

All original Wikipedia text is distributed under the GFDL and CC-BY-SA licenses. Occasionally, Wikipedia articles may include images, sounds, or text quotes used under the "fair use" doctrine of United States law.