Amie Street was developed about 4 years ago and makes songs available through a distinctly democratic system- based on popularity. Variable pricing, as it’s called, has worked well for Amie Street, who has partnered primarily with small labels through The Orchard. That’s about to change- Amie has made a deal with Sony. See more over at TechCrunch.
While the Sony deal differs from Amie’s usual model, Michael Arrington says this is hopefully a step toward something “purer.” It makes sense to me that new, unheard artists work well through this system- (the songs are free and then go up in price the more downloads the song garners). I’m not sure if this will work for an already established name.