Wikipedia

Wikipedia is a collaboratively edited, multilingual, free Internet encyclopedia that is supported by the non-profit Wikimedia Foundation. Volunteers worldwide collaboratively write Wikipedia's 30 million articles in 287 languages, including over 4.4 million in the English Wikipedia. Anyone who can access the site can edit almost any of its articles, which on the Internet comprise the largest and most popular general reference work, ranking sixth globally among all websites on Alexa with an estimated 365 million readers.
Physical address: 
San Francisco, CA
United States

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There are currently 385 Commons-Based Peer Production cases!