Last.fm offering full-length tracks
I've been tracking what I listen to at last.fm for a few years. It's an awesome service to discover new music from network-based recommendations, but the ability to preview whole tracks from artists you'd just found was limited.
iTunes and their shitty 30 second previews can officially suck it.
Basically two ways to have last.fm track your music.
1. You can download their client (win/linux/max) and listen to music through that player. http://www.last.fm/download/
2. You can download a plug-in for one of several media players (itunes, windows media, winamp, etc) and have that send the tracks you listen to back to your last.fm account. http://www.last.fm/download/extras/
That forms the database of music for your account and from there, you can make your own stations, listen to tracks, explore recommendations through friends, view your listening over time.
It's for people who like their music AND their data.