As noted by TechCrunch, Apple appears to be leveraging their unique position as App Store curator in their upcoming iAds service.
The above slide shows Apple's ad company Quattro Wireless pushing a program to potential iPhone app advertisers called "Verification of iTunes Purchase" (VIP). The program allows advertisers to track actual App Store purchases to measure an ad's performance. Apple can then use this knowledge to prevent the ad from being displayed to that user again. While this sort of ad conversion tracking is routine on the web, it is a bit more complicated for 3rd parties on the App Store.
Ad companies such as Admob do provide a similar feature but it requires code modification to the target app to track usage. Apple, however, has already taken steps to make this feature difficult for 3rd parties to offer. Apple's latest SDK terms stipulate that Apps may not "collect and send Device Data to a third party for processing or analysis". This restriction is the source of some debate as well as a topic of the FTC investigation into Apple.
Article Link: Apple Leverages App Store Data for iAds