The Echo Nest web music API is fairly awe inspiring. For example, they have a web service to detect the sections of a song — bridge, chorus, etc. — given only an MP3. What it amounts to is a bot capable of doing semantic analysis of a sound file.
One thing you could do with it is to distinguish spoken word from music files. A hosting service could then automatically reject music but allow talk, which would control its legal liability.
All in all it’s a radical level of power for the kind of lightweight apps that use third party web services.
One complaint so far: the web service returns XML, but the XML isn’t in a namespace. This will cause pain down the road, and it can easily be alleviated by adding an xmlns=”http://echonest” attribute to the root element.
Does that work, distinguishing spoken word from music? That would be extremely useful.
I’m not sure about that namespace recommendation though – just makes it harder to process, in my experience.
In case you didn’t see this write-up about using the Echo Nest Remix API:
http://musicmachinery.com/2009/06/21/wheres-the-pow/
“. . . You use all of the tools that you use in the audio remix, except that the object you are manipulating has a video component as well. This makes it easy to take an audio remix and turn it into a video remix. . . .”