I finally got around to exploring
Pandora radio (which I first encountered the last time I worked at the museum store). I have to say it is majorly weirding me out (but in a good way).
Pandora is the result of the Music Genome Project, a research group which is systematically cataloging and analyzing songs. You tell it to create a "channel" based on an artist or song you like, and it creates of mix of songs the MGP has deemed to be similar. The results are eerily telepathic. For instance, I made a "Peter Gabriel" channel, and every single song has been one of my favorite songs, or a song by a favorite artist I hadn't heard; so far it's thrown in Sting, U2, Pink Floyd (80s-90s), Depeche Mode, Genesis, the Police, Talking Heads, and Simple Minds. I keep going, "Why yes, I also like that song... how did you know??" A channel based on an artist I'm less familiar with brought up a host of artists I've never heard of but also really like. Then you improve the mix by telling it which songs you do and don't like. It works much better than Last.fm, and it's all complete songs, not just snippets like a lot of what's on Last.fm. There is intelligent commentary on each band and the characteristics of each song (it totally feeds my fascination with analyzing stylistic hallmarks!). Plus, it's all legally licensed, and the artists actually get their royalties when you listen to their song.
So far, the limitations are that you can only skip 6 songs per hour (but you can always go to another channel), you can't preview what's coming up, and you can't replay a song right away. Also, it will go to sleep if you don't click on the window periodically, and it only works in the US for now. But basically it's like having the best radio station ever... very cool! (And also bloody distracting!)