Apart from the obvious example of Myspace, there are no any number of different places that musicians can get exposure on the Net. From what I have seen on a lot of these sites, the trouble seems to be that a lot of musicians approach these sites with the wrong attitude.
One of the dynamics of the musician in the context of the traditional music industry is the  aloof nature of the position the successful musician finds himself in. Many musicians approach the Net and try to create the same adoring distance among the fans on the Net. This will simply not work. An underlying tone that demands adoration (while not the most pleasant way to go about things) will work if the first contact with a new fan is in the context of a traditional media outlet such as television. The new fan will perceive the artist on Television as already ready rich and famous so arrogance and swagger will not alone be tolerable, it will probably be appealing.

Expecting reverence and adoration while broadcasting to the Net from the comfort of your Mother’s basement however, will probably not pack the same punch. You need to personal in your approach. Nobody owes you anything so when people appreciate your music, keep your tone thankful and pleasant rather than treating them like they have just finally come to their senses by realizing that you are actually a God after all.

If you’re main interest in music is the giant ego trip and wanting to be treated like a celebrity then I have an alternative piece of advice for you……………

Just forget it and find something else to do with your time.