Below is a list of websites like Pandora / services like / similar to Pandora :
The Music Genome Project is one of the most comprehensive analysis of music ever undertaken. Together our team of fifty musician-analysts has been listening to music, one song at a time, studying and collecting literally hundreds of musical details on every song. It takes 20-30 minutes per song to capture all of the little details that give each recording its magical sound - melody, harmony, instrumentation, rhythm, vocals, lyrics ... and more - close to 400 attributes!
With Pandora you can explore this vast trove of music to your heart's content. Just drop the name of one of your favorite songs or artists into Pandora and let the Genome Project go. It will quickly scan its entire world of analyzed music, almost a century of popular recordings - new and old, well known and completely obscure - to find songs with interesting musical similarities to your choice. .