Wikipedia

Wikipedia is a free, web-based, collaborative, multilingual encyclopedia project supported by the non-profit Wikimedia Foundation. Its 15 million articles (over 3.3 million in English) have been written collaboratively by volunteers around the world, and almost all of its articles can be edited by anyone with access to the site. Wikipedia was launched in 2001 by Jimmy Wales and Larry Sange and is currently the largest and most popular general reference work on the Internet.
Although the policies of Wikipedia strongly espouse verifiability and a neutral point of view, critics of Wikipedia accuse it of systemic bias and inconsistencies (including undue weight given to popular culture), and allege that it favors consensus over credentials in its editorial process. Its reliability and accuracy are also targeted. Other criticisms center on its susceptibility to vandalism and the addition of spurious or unverified information, though scholarly work suggests that vandalism is generally short-lived, and an investigation in Nature found that the material they compared came close to the level of accuracy of Encyclopædia Britannica and had a similar rate of "serious errors."
Wikipedia's departure from the expert-driven style of the encyclopedia building mode and the large presence of unacademic content have been noted several times. When Time magazine recognized You as its Person of the Year for 2006, acknowledging the accelerating success of online collaboration and interaction by millions of users around the world, it cited Wikipedia as one of several examples of Web 2.0 services, along with YouTube, MySpace, and Facebook. Some noted the importance of Wikipedia not only as an encyclopedic reference but also as a frequently updated news resource because of how quickly articles about recent events appear. Students have been assigned to write Wikipedia articles as an exercise in clearly and succinctly explaining difficult concepts to an uninitiated audience.
The word Wikipedia ( /ˌwɪkɪˈpiːdi.ə/ or /ˌwɪkiˈpiːdi.ə/ WIK-i-PEE-dee-ə) was coined by Larry Sanger and is a portmanteau from wiki (a technology for creating collaborative websites, from the Hawaiian word wiki, meaning "quick") and encyclopedia.