Wikipedia
From Peter Gelderloos, Anarchy Works:
Started recently, in 2001, on Open Source Linux software, Wikipedia is already the largest and most accessed encyclopedia in the world, with over 10 million articles in more than 250 languages. Rather than being the exclusive domain of paid experts from a particular academic subculture, Wikipedia is written by everyone. Anyone can author an article or edit an existing article, and by allowing this openness and trust it provides a forum for instantaneous, multiple-peer review. The interests of the broader Wikipedia community of millions provide a self-regulating function, so vandalism — false editing and bogus articles — are quickly cleaned up, and facts lacking citations are challenged. Wikipedia articles avail themselves of a vastly greater body of knowledge than the small and generally elitist circle represented by academia. In a blind, peer-reviewed study it was judged to be as accurate as Encyclopedia Britannica.[1]
Wikipedia is “self-organizing” and edited by an open body of peer-elected administrators.[2] There have been a few publicized cases of intentional sabotage, such as when the televised news comedy show The Colbert Report rewrote history in one Wikipedia article as a gag for their show; but the prank was quickly fixed, as most false information on the site tends to be. A more lingering problem is posed by corporations who use Wikipedia for public relations purposes, tasking paid personnel to maintain a clean image in the articles about them. However, contradicting interpretations of the facts can be registered in the same article, and Wikipedia contains much more information on corporate misdeeds than any traditional encyclopedia.
