Pandora is a free music service with a unique focus, the Music Genome Project. Since 2000, the company has been analyzing music into "genes," such as major or minor key tonality, gangsta rap attitude, avante-garde leanings, ambient soundscapes, a vocal-centric aesthetic, and my favorite, excessive vamping. Here is Wikipedia's list of Music Genome Project's genes. Go in, type in a song or a band you like, and Pandora will play other songs with a similar musical genotype. Then if you register, you can create a number of personal "channels."
Tim Westergren, Pandora's founder, is coming to speak in Nashville next Thursday night. It's at Bongo Java After Hours. It's free and open to the public, but you need to RSVP at email@example.com. Most likely that same email address would be where you'd write if you're wondering whether Tim will also be coming to your city.
I've known about Pandora for a year, and honestly haven't done much listening to it, but I'm going to commit to it from now til next Thursday so that I can get the most possible out of the event. I am finding so far that the best strategy is to find a number of channels you like, then hit "Quick mix" so the player can mix it up -- otherwise it gets pretty repetitive. Biggest musical surprise of the morning: a Radiohead song came up for me! And I actually liked it!