Musicans go where there are listeners and other musicians. And, listeners go where there are musicians and other listeners.
Those connections between musicians and listeners are, on one level, what we now call “web-like” connections. Fortuituously, the WWW offers all kinds of ways for people to create web-like connections!
Practically, right now, MySpace offers some efficient ways to connect, having your own blog offers other ways, being listed on Wikipedia other ways, etc.
But, if you, as a musician, want to keep exicitng the web around your music, you ultimately have to recognize that the “generate a web for you” services like MySpace aren’t tunable to your unique web. You need, at least, one of your own domains / websites that you can fully tune to the web around your music (e.g., that encompasses your web on MySpace and all the other sites like it).