I love technology that tries to figure out what TV shows, music, or other products I will like -- though, frankly, Amazon is getting the wrong idea about my taste in music because of two products I bought as gag gifts.
Launch, which was recently acquired by Yahoo, asks you to pick 8-10 of your favorite artists and uses them as the basis for your own personal radio station. As a song is being played, you can rate the song, album, and musician on a scale of 1 (barely tolerable) to 100 (incredibly great) or give it a 0 to stop the song immediately and never hear it again. Songs by your favorites are played along with songs that are rated highly by other people who like the same things. You can also listen to the stations of other users -- such as the Launch station of Rafe Colburn, publisher of RC3.org. (Didn't picture him as a Merle Haggard fan.)
Launch does a pretty good job of programming a radio station to my tastes, though it doesn't stray far enough from mainstream artists (or maybe I don't!). The service also puts two- or three-song blocks of current pop or rap dreck together at least once an hour, presumably in some kind of payola deal with a record label.
The nicest thing about the service is when it calls my attention to an artist I like before I know I like them. Apparently, I'm a huge fan of Woody Herman, Weezer, and Veruca Salt, though I didn't know this before Launch started playing them for me.