Apple is enforcing every iPhone/iPod Touch developer to ensure that their applications are compatible with the new iPhone OS 3.0 (which right now is in beta 5 version).
We are getting closer to the moment of the official release and Apple wants to make sure that every application that is right now in the App Store or new apps will work with the new iPhone OS 3.0.
It’s supose that they should work just like that, but some of them could need a tweek and they want to be sure.
Apple has began to review the actual apps and added as part of the aproval process for new apps, to make sure they work well in the new OS 3.0, and any application that doesn’t meets this requirement will be removed from the App Store or denied (if is new).
It’s a good way to ensure that all the users will get good quality apps and that they will not get issues when they upgrade their iPhone/iPod Touch devices to the new OS 3.0 this summer.