Lawrence Lessig has a nice piece in Wired about Jeff Tweedy and Wilco.

“Music,” he explained, “is different” from other intellectual property. Not Karl Marx different – this isn't latent communism. But neither is it just “a piece of plastic or a loaf of bread.” The artist controls just part of the music-making process; the audience adds the rest. Fans' imagination makes it real. Their participation makes it live. “We are just troubadours,” Tweedy told me. “The audience is our collaborator. We should be encouraging their collaboration, not treating them like thieves.”