John Mayer launched his new tour site today with an awesome networking and collaboration component demonstrating a musician truly connected with his fans.
Similar to the way Barack Obama's site localizes content for users based on their location, Mayer's site includes a show page for each night of his tour. Within that page (here's one) exists functions for fans to upload videos, photos, reviews and, in keeping with Mayer's word, full show recordings. Fans can also vote on the encore selection before the show, and return back to see "official" multimedia after the experience.
The site is attempting to harness the torrenting and file swapping practices already exhibited by Mayer's fans on message boards. So long as the technology holds up, I bet you it will work.
Blackberry, a sponsor of the tour, also has a mircrosite lurking in the corners. As of writing, however, that site is not yet live.