With regards to Wikipedia, a friend of mine from university said that when he was at school, some of his friends edited the page of some obscure bacterium to say that he was the discoverer of it. However, they didn't tell him until after about two years, at which point it still hadn't been changed. If any grad student had just looked up Wikipedia and not, say, a textbook/journal article and put that down, that could have meant serious punishment for them!
So, the lesson is: if you want to use Wikipedia, check your sources!