Via history_doc, this article: The Bigger Picture: Muppets, Avengers, and Life In The Age Of Fanfiction.
I thought it was an interesting article. As I said over in the comments at history_doc's I've often thought that TPTB shouldn't be so dismissive of fanfiction, as it seems a lot of what's being put out these days fits the whole fanfiction vibe. Like The Avengers, for example - you've got Joss, big damn fanboy, and a lot of the cast, who are comics fans. It's like when you were a little kid and would play act some favourite character from a book or media with your friends, except they get to do it officially and get paid for it.