From the Associated Press, a story about politics in the state of Georgia:

The campaign manager for Secretary of State Cathy Cox resigned on Wednesday amid allegations that he altered an online biography of her Democratic opponent to add a mention of his son’s arrest in a fatal drunk driving accident.

Cox said an internal investigation confirmed that the posting about her opponent, Lt. Gov. Mark Taylor, on Wikipedia, a popular online encyclopedia, came from within her gubernatorial campaign.

I would like to think, the act of someone editing Wikipedia in and of itself is not a sin. But using Wikipedia as a venue for putting embarrassing facts to discredit an opponent should be frowned upon.

Interestingly, this should remind readers that actually not “logging in” is less anonymity than creating a username because Wikipedia records your IP address in the edit history instead as the “user.”
Beware this operational aspect of wikis when not logging in.