About 40% of CDs Played on Computers Are Custom Mixes

I recently interviewed Gracenote cofounder Steve Scherf to try to get to the bottom of all of the rumors and ill will surrounding the company. The interview, which should be posted early next week, contained the following snippet which I think is pretty interesting on its own:

"A good number of [the CDs Gracenote identifies] (we estimate about 40%) are people's custom mix discs, and not commercially available in any way. We actually don't mind people submitting personal burns to the database. Sometimes they actually get popular and get distributed to numerous people, and it's a great thing when Gracenote recognizes the disc for those people. We can tell these apart from commercial discs."

I wonder whether these will ever be released in chart form, because I'd love to see a list of the top ten most widely-distributed mix CDs in the world. Whoever originally burned the most-traded CD could probably get a job making playlists for an online music service.