How to delete a Last.fm account?
The description of the service:
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.
After deactivating your account, you are able to restore it at any time by logging in. There does not appear to be a point after which your data is actually purged.