In addition to multitasking, iPhone OS 4.0 introduces the iAd framework for delivering ads in your application. The following section details how you can generate additional revenue in your apps by displaying ads.
You might be wondering, “Why on earth would I want to annoy my users with ads?” The answer: Using ads, you can release your app for free while still generating revenue.
You might also be thinking, “Mobile ads are awful.” Apple agrees with you. In fact, Steve Jobs noted the poor state of mobile ads during his keynote introducing iPhone OS 4.0. Just as the iPhone was a reimagining of the mobile phone, iAd is an attempt to revolutionize mobile ads by providing nothing but beautiful, high-quality ads to users.
How It Works