Belatedly, I've finally looked at Exit Through the Gift Shop. Some movies have a "long finish." I dreamed about Exit last night and it was in the forefront of my consciousness today. I expect to be considering it from different angles all week.
There's nothing to be said about the film if you haven't seen it. However — if you have seen it and are still thinking about it, too — at the moment I concur with Matt Cale's smart parsing at Ruthless Reviews.
The New York City edition of Banksy's website has a month's worth of brilliance on offer. I may even make the T-shirt.