Mass-patronage model: sell music, not copies

I find myself wondering how well Joss Whedon and Co. are doing on Dr. Horrible's Sing-A-Long Blog, which is attempting a patronage model and episodic releases for a musical comedy about super heroes and villains.

I can't help but think a new model is developing, and it will probably work for music, as well as movies and television shows. But, I'm not sure it's going to look exactly like the patronage model described...but probably close enough, if you squint.

An implementation could be a tipjoy button on last.fm or alike.