Reporting of child pornography images on Wikimedia Commons 2006 he founded Citizendium, a competitor to Wikipedia. While Sanger has gone on the record that this was not an attack on Wikipedia, nor a way to boost readership of his own free web-based collaborative encyclopedia, there is a significant level of skepticism that Sanger acted without malice. Sanger has had an antagonistic history against Wikipedia since leaving, including criticism of Wikipedia co-founder Wales, and of the Wikipedia community: "The ... community had essentially been taken over by trolls to a great extent. That was a real problem, and Jimmy Wales absolutely refused to do anything about it." Fox News
Jimmy Wales the Nupedia and Wikipedia projects until Bomis discontinued funding for his position in February 2002; Sanger resigned as editor-in-chief of Nupedia and as "chief organizer" of Wikipedia on March 1 of that year. Early on, Bomis supplied the financial backing for Wikipedia, and entertained the notion of placing advertisements on Wikipedia before costs were reduced with Sanger's departure and plans for a nonprofit foundation were advanced instead. Wales has asserted that he is the sole founder of Wikipedia, and has publicly disputed Sanger's designation as a co-founder. Sanger and Wales were identified as co-founders at least as early as September