This works a lot like Myspace. You fill out (or select from the existing list) Artists and Albums you like.
Others do the same.
What you end up with is a relative degree of similarity determined by everyone's lists. So if you like Nine Inch Nails, you can easily find a whole list of music you will probably also like.
Don't forget to copy this and post a new bulletin and put it in your LiveJournal/DeadJournal, email it to friends, etc. The more people we have, the better it works, and the goal is to have 1,000 new users this week.