In a piece for Ars Technica, author Nate Anderson opines:

“Distributing the cash fairly would require knowing how much people actually listen to specific tracks, which means software embedded in players or on users’ machines. And how many consumers are going to be excited about this?”

This software already exists—last.fm’s Audioscrobbler application tracks and reports the listening habits of 5 million people. A small fraction of the population, but strong evidence that users will trade a certain level of privacy in exchange for entertainment value.