Perhaps stupid question: Where is the music stored?

[mic9]

This project looks promising, but I'm still trying to figure out a few things about how it's actually going to work. 

Who holds the music?  Is the artist required to maintain his own server which stores the music?     I mean supposing I just want to throw a bunch of my own jams and crap out there - do I need to have a server for this or will the network just decide to keep my music available for me?