Mashes Weblogs have made DRM for text useless. It doesn't matter how sophisticated Salon or Slate become about locking up their content, people are too busy reading weblogs to care (or notice).

I've been looking out for the same phenomenon for music. Unknown garage bands get no traction on Napster because no one knows them and there's no difference between downloading a famous hit or obscure dud. I don't think mashes are 100% of the answer, but I think they'll play an important part.

Vinyl singles sometimes contain the complete song as well as decomposed a capella tracks which isolate, say, the music from the vocals. This allows DJs to play the vocals of one song against the music of another producing a "mash-up" that's proven a big hit in clubs. Inevitably, some of these mash-ups are released as combined tracks, and become illegal derivative works under current copyright law.

In this excellent BBC documentary, one of the DJs points out that if the labels really wanted to stop mash-ups, they should just stop releasing a capella tracks. The recording cartel likes mash-ups because they breathe new life into 10-30 year old songs which are still under copyright but no one buys. So a wasteful rent-seeking (are there other kinds?) legal apparatus has sprung up where mash-ups are supported through a capella tracks but legal heavies swoop in to extort money from anyone who becomes too successful.

This selective enforcement of law means property rights around a capella tracks are poorly defined, leading to terrible waste (the Coase Theorm). I'm guessing that this legal murk will eventually be cleared by registering a capella tracks under copyleft style licenses, perhaps developed by the Creative Commons, so DJs know what they can and cannot do with a capella tracks. Once labels start competing to offer better terms to DJs, barring collusion, they'll be forced to price at marginal cost and give the tracks away.