Here's some recent research findings from Ipsos' TEMPO Digital Music Discovery & Purchase Process. Evidently, subscriptions and paid downloads are barely outpacing ad-supported services like MySpace Music, but once newer innovative services like Spotify are legalized in this country - I think ad-supported will dominate as the preferred legal distribution and consumption model.
""The fee-based digital music market has likely reached a state of maturity in terms of who is paying to download and stream. The goal, now, will be to expand recurring revenue streams and to attempt to increase the volume of content that is purchased among those already making digital music purchases. Meanwhile, the ad-supported models are proving to be an effective means of expanding the broader, legitimate market beyond just the fee-based realm."