Wikipedia Vs Britannica
The current issue of the international weekly science journal, Nature, has a special report comparing the accuracy of science articles in Wikipedia with the accuracy of the Encyclopedia Britannica. Their conclusion is that the "accuracy of science in Wikipedia is surprisingly good: the number of errors in a typical Wikipedia science article is not substantially more than in Encyclopaedia Britannica, often considered the gold-standard entry-level reference work." Wikipedia also attracts an editorial comment arguing for scientists to become more involved in generating content for Wikipedia.
Special Report: "Internet encyclopedias go head to head":
www.nature.com/nature/journal/v438/n7070/full/438900a.html

Editorial: "Wiki's wild world":
www.nature.com/nature/journal/v438/n7070/full/438890a.html