fred Wilson raps about Last.FM again. He calls it myware and defines myware as a program that one might use to spy on oneself. Why would one let that happen? Last.FM's music recommendation service and "I-like-that-music-too" people matchmaking service are a few potential benefits:

Last.fm is a music service that I've written about in the past. You download and install some "myware" that last.fm provides and it tracks the music you listen to in iTunes, Winamp, Yahoo!,and a number of other music services. Your music listening history is shown on the web to you, in case you are interested in seeing what you've been listening to, and everyone else. In addition, last.fm has a music player that creates a streaming audio/internet radio channel just for you based on what you've been listening to. And, most importantly, last.fm creates a social network for you by linking you to people who share your music tastes. It's a great service and I use it all the time to find new music.

With the recent acquisition of webjay by yahoo, I'd imagine that Last.FM isn't far behind.