Wikipedia was launched on Jan. 15, 2001, by Larry Sanger and Jimmy Wales as an online encyclopedia with a limited editorial review process. Contributors began adding content rapidly, and Wikipedia grew to more than 20,000 articles in 2001. The website expanded into the international sphere, and as of 2014, more than 85 percent of the content is in languages other than English. As of October 2015, the Alexa website ranked Wikipedia as the seventh most popular website on the Internet.
Throughout its history, questions of accuracy have plagued Wikipedia. Sanger created the first set of content guidelines in 2002 to address the problem; the rules evolved slowly over Wikipedia's lifetime. Sanger left the company later in 2002 as concerns of legitimacy grew and the dot-com bubble burst. Although the website does not have a core editing staff, it uses volunteer editors to flag and change incorrect content.
Wikipedia was initially founded as a companion site to Nupedia, a website that published expert peer-reviewed content. Wikipedia quickly eclipsed Nupedia, which folded in 2003.
In 2003, Wales founded the Wikimedia Foundation to provide funding and guidance for Wikipedia. In 2004, Wikipedia launched Wikimedia Commons to host all of the images and video files used in Wikipedia's articles.