When someone alters a Wikipedia article to win a specific argument, anyone who reads the false article before the "error" is corrected suffers from collateral misinformation.
I changed the scientific classification of red foxes last night in order to win an argument with Judy. I hope some stupid High School student didn't suffer from collateral misinformation.
Urban Dictionary, of course, is completely unreliable, and is itself constantly gamed in this way. Still, I love the concept. There's something wickedly post-modern about it.