At Apple's big event Tuesday, Sept. 10, we expect more insight into iTunes Radio, a key feature of Apple's new operating system, which we expect to launch a week later.
The free, ad-supported streaming music service is a move in a totally new direction for Apple, which has built its business on selling gadgets as well as content. Though subscribers to Apple's iTunes Match cloud music service will be able to listen ad-free, the core product is targeting the much larger audience of people who don't subscribe, to listen for free with audio and video ads.
(Read more: Apple sends out invitations to Sept. 10 event)
Apple is looking for a piece of the $15 billion dollar radio advertising market, which RBC Capital Markets' Mark Mahaney said could be worth as much as $25 billion when including video ads. Apple has had a poor track record with advertising—its mobile ad platform iAd was far from a success—but so far sources say it's gained great traction from big name-advertisers.