Audioscrobbler is an amazing community music tracking application that is really starting to gain some steam. The premise is pretty simple, you run a small app on your deskop which sends information about what songs you are playing on your computer’s MP3/CD player. Now that they have thousands of regular users, they aggregate the information and produce weekly charts and allow even record-at-home musicians to see who is listening to their music.
To promote more interesting uses of the data, they also offer it for download (anonymous data — user details are stripped) to developers, under a Creative Commons license. This makes perfect sense, as they don’t want users and developers to have to wait for Audioscrobbler to program new features or views of the data. With the license they can open it up to anyone that is interested in doing cool stuff with it, but they also want to protect the data from being exploited for commercial reasons and resold.
This originally started as a student project for a computer science course and a little over a year later it’s turning into a bustling community that may someday rival things like pop music charts and sales data.