Influx

Napster is dead but Peer to Peer networks are alive and well under different names, with slightly different models that evade copyright laws. These are Kazaa, which has 200 million registered users, Imesh, FastTrack and Limewire. Users share not only MP3s but also videos (including bootlegged prerelease Hollywood features) and software (much of it ‘cracked’ or pirated.)

This media landscape of free availability can be tracked and mined for up-to-the-minute trends. An example is BigChampagne.com which maintains a chart of the songs and artists most downloaded on peer to peer networks.
http://bigchampagne.com/