Last.fm

Last.fm is a music community website that offers personalized internet radio, using a recommendation system called “Audioscrobbler” to build a detailed profile of users based on their music tastes and interests. The service installs plugins into the user’s media player and automatically profiles the songs he/she listens to.
The service will offer recommendations and a ‘personal’ radio station based on the user’s listening patterns.

As of early 2009 last.fm charges 3 EUR/month subscription fee to allow listening to music on their website.
Paid features include:

Unlimited radio streaming
Ad-free browsing and streaming
Recent visitors to your profile
A prestigious black icon
Access to the VIP zone with more charts, graphs and the latest from the Last.fm Labs