Mercora is a startup that is going to utilize social networks (and maybe collaborative filtering) to distribute DRM-protected music.
The economics of this (if it works) are pretty simple: the extra value you get from having your online buddies turn you on to new stuff is greater than the cost of the hassle that the DRM imposes.
Interesting, to say the least - at least they are creating value. They haven't signed any deals with record labels yet, so don't hold your breath.
The website is SO 1999 - it says 'the revolution begins'!!! Aw, I'm getting all teary-eyed.