Last.fm has deals that allow them to stream over five million full tracks for free. That's increased their on-line minutes and sales dramatically, according to Wired on Thursday. The conclusion was that exposure to free music has lead to increased sales.

The increase in sales has been due to referrals, but existing users have driven sales up 66 percent since the free music program started. Last.fm has concluded that free music has increased demand for sales. [The streamed, full track music is free to listen to but cannot be saved.]

The thinking is that the more music people hear, the more music they want to buy.

"In just over two months it's become clear that people will buy CDs and downloads if they get access to the kind of service we offer," said Martin Stiksel, a co-founder of Last.fm. "No one else can give music fans this amount of music for free -- but more importantly also drive their discovery, as we do through our unique recommendation engine."

Mr. Stiksel added that since the program started, minutes spent on the site are up 118 percent month-over-month.

Currently, Apple's iTunes allows only a 30 second preview of a song before purchase and contains only a smattering of free content. While Apple would surely want to increase listenership with free, streamed only music, it's also likely that the Labels experiment with different business models to maximize revenue. As a result, it's unlikely that iTunes and Last.fm will ever have identical business models unless the Labels think that's more profitable.