I am in love with the Pandora.com. There could not be a more cool website for music. For those of you who have never experienced Pandora, it is a music genome project - so to speak. Just as in the human genome project, the folks behind this site have broken down hundreds of musical attributes (genes) and have created a music genome. These "genes" take into consideration every element of a song - such as lyrics, harmony, melody, rhythm, instrumentation, arrangements etc. Net, each band has a genome. Imagine the basic science principle of genus and species (e.g. homo sapien) used with music - and then taken even deeper. This my friends is the essence of www.pandora.com.
But they take this process one step further. You start the process off with selecting a song or band. They then play you a song from that band. You then can approve or reject it (thumbs up or thumbs down). Depending on what you chose, the program either retains or rejects any new songs from this artist or other like artists (with same genome) based on the genes of that song. In short, the program intelligently begins to create a play list for you bast on the genes you select or reject. Then you can set up various play lists based on various bands or songs for any mood you are in. It's excellent!