"The new OS, iPhone 3.0, will support 1,000 APIs. Apple seems to be giving a lot of extra love to paid apps, which will gain the ability to sell additional levels, subscriptions, virtual goods, or extra content from right within the app...
Apple is not opening up background processing, which would allow more than one app to be running at once—a feature already common on Android and other phones. Apple says it takes up too much battery life.
Apple is also opening up push notification APIs for developers. This will allow apps to incorporate email, IM, and other messaging services."
