Last.fm is a music discovery service that gives you personalised recommendations based on the music you listen to.

Last.fm is a music website, founded in the United Kingdom in 2002. Using a music recommender system called "Audioscrobbler", Last.fm builds a detailed profile of each user's musical taste by recording details of the tracks the user listens to, either from Internet radio stations, or the user's computer or many portable music devices.
The free user account includes access to all the main features listed below. Registered Users are also able to post in the Last.fm forums, send and receive private messages and use the Last.fm client music player. For users living outside the UK, US and Germany, the radio service will require a subscription for €3.00 per month after a 50 track free trial.