A few years ago, a dear friend of mine worked for Uplister, a notable dot-com failure. Notable, that is, because of the fabulous idea at its core. It allowed people to create music playlists for one another, and provided a means for individual list creators (DJs, if you will) to gain their own followings. You could search for like-minded music lovers by means of mutually cherished songs. Amazon.com is among the companies now utilizing this idea to create customer-driven cross marketing.
Great idea. Lucas Gonze, a deep thinker in the music P2P scene, has now created Webjay, a noncommercial application that does something similar. Rock on.