Jonathan Edwards :

App Ads are potentially a Google-scale cash flow, and Jobs wants it. He wants to sell ads and inject them into apps on the iPhone/iPad/iDesk, just like Google injects ads into web pages. He can’t do that unless all the apps are using his libraries. If he lets Flash apps in, then Adobe would be able to sell the ads instead. That is why section 3.3.9 of the new developer agreement says “the use of third party software in Your Application to collect and send Device Data to a third party for processing or analysis is expressly prohibited”. Like, for example, Ad networks.