"A man in Nashville has admitted that, in trying to shock a colleague with a joke, he put false information into a Wikipedia entry about John Seigenthaler Sr., a former editor of The Tennessean in Nashville." - NY Times
"In a confessional letter to Mr. Seigenthaler, Mr. Chase said he thought Wikipedia was a "gag" Web site and that he had written the assassination tale to shock a co-worker, who knew of the Seigenthaler family and its illustrious history in Nashville." - NY Times
Of course you thought wikipedia was a gag site! What a moron. Ironically, Chase now has a Wikipedia entry. (Currently under consideration for deletion.)
Wikipedia has some detractors: http://www.wikipedia-watch.org/
I'm not a purist when it comes to the "right" of anonymity of the internet. In general, I think everyone should have to stand by what they say and do on the internet - as they should in "real life." However, there are times when doing that can get you killed or put in jail.. even here.. Perhaps Wikipedia should work to get the users trust enough to privately manage identities. I believe that Wikipedia has already placed restrictions such that only registered users can create new pages.