I saw this documentary a couple of years ago. It's worth watching. Banksy is a cultural phenomenon. You have to admire a person who can craft such an intriguing persona around himself, yet still be able to pretend that he had nothing to do with it, and that it just arose naturally from the public reaction to his work. The guy is such a master manipulator, at first glance it doesn't look as though he's manipulating anything. It looks as though he creates a picture, and everyone just somehow reacts with wonder and admiration. Yet somehow it kept happening year after year. There are countless artists more talented than Banksy who couldn't get people to notice their work if they walked with it in front of a speeding bus.