My brother pointed me to http://www.pandora.com. Apparently a bunch of people collected high level descriptors for thousands of musicians and their songs. One of the things they can do with this information is suggest music to listeners.
Collecting lots of metadata deliberately from humans is hard. Yet it can provide some very useful applications. Amazons “Users who bought this also bought” system which rarely tells you something new, or purely software analysis that only tell AI nerds what they already know could benefit from this meta data.
Another thing floating around the internet is this http://tones.wolfram.com/generate/.
But I can’t get it to play.