What looks interesting is the ability for the artists to interact with the fans like they would on FB/Twitter on the same medium they could sell their music (I don't think there will be selling of music on the Mega project though).
Right now we have FB/Twitter where it is very easy to keep in touch with the artists and build a relationship and maybe find new ones but no real way to sell things that well. Then their is iTunes where you can buy music but no real community aspect.
I think bringing them together will be interesting. I could see something like a Kickstarter aspect working as well. Fans doing something like we want to see Kanye and Bieber do a song together. People could then show support etc and help chose what gets made.
Ultimately though it has to really help new/unknown artists get started. It's great that Louis CK can sell his stuff online by passing the record companies but that is unrealistic for most people. I system that provides a great community with a great "discovery" aspect could really help this. Fans could be like "I want a song made about blah blah" and some random artist could deliver. Maybe if you are doing a show somewhere you also film it and throw it up on the site for people to watch. Random thoughts. But I hope these provide some exciting opportunities for artists!