In answer to the threads title. Stability.
Apple's idea of keeping a persistant IP connection to any applications that need it, is a very good substitute to running background applications.
You think the battery life is bad now? - Just you watch how many hours you'd get, if they allowed you to run Palringo Messenger, Maps, and other high CPU-intensive applications.
Also app caching will cause applications to crash less frequently.
Apple are doing right in providing a solution to a problem that actually does need resolving.
I imagine the Push Notification Service to act exactly as if the application were still running, only, it won't be.
This is a good move on Apple's part, and will benefit both developers, Apple and us in the long run.
Be patient.
R-Fly
doesn't anyone else find 'stability' to be such a silly copout explanation? are we really to believe that iphoneOS would have stability issues if it ran more than one app?
i still fail to see how push notification is really going to solve anything. i still have to shutdown whatever app i'm already in, in order to get to the app that gave me a push notice don't i?
anyway this is my first mac product and although i believe i did my fair share of research before buying my 3g, i had no idea that multi-tasking was even an issue until i got the thing.
as for the person saying memory leaks don't happen on the iphone, you are dead wrong. good luck trying to close the 'crashrepor' process when it has started.