A co-worker showed me Pandora today. It's an online music service for finding new music. You give it a song or an artist, and it creates a "radio station" of songs similar to yours. As it plays songs, you can give them thumbs up or down to adjust the heuristics. When you give a song a thumbs-down, it skips the song, unless you've given too many thumbs-downs. In that case, it continues playing the song, and adds helpfully:
Unfortunately, our music licenses force us to limit the number of songs you may skip each hour.
Odd. If you start with an artist, the first song is by that artist. If you start with a song, it doesn't start by playing the song, explaining that their music licenses prevent them from playing specific songs by request. Very odd.
I tried it all day today. I thought it did a very good job picking songs I would like, including a couple of dozen artist I had never heard of. The first ten hours are free, and then you have to pay, but the rate is the very reasonable $36 per year. I think I'll be subscribing.