Pandora

Part of the Music Genome Project, Pandora is a music recommendation tool that bases its recommendations not on ratings by users, but on the tonality, rhythm, and vocal characteristics of specific songs or bands. You simply type in your favourite band name, and up pops your recommendations. I tried it for a few bands and was impressed, as it recommended a good number of groups I'd never heard of, as well as some others I knew and enjoyed. You can try it free for ten hours, but after that, it's $36 a year.

(via Futurismic)