"Apple says there are seven services you can use for background tasks, but you can't write your own multi-tasking capabilities into a [software] program," analyst Gold says. "There are limits to multi-tasking [being] available. This may be an issue for companies that do a lot of background processing, like say, running a database or reporting on a device in background."

Multi-tasking will also enable continuous "live" location tracking in the background via GPS, or via less-precise cell tower triangulation (or presumably via , since iPhone supports that feature also).

In today's presentation, Apple executives didn't go into details on how multi-tasking applications will be managed, especially if badly coded apps become especially demanding in their memory or power requirements.

Apple has been criticized for not letting developers exploit the multi-tasking features in the OS, which Android and the older Windows Mobile platform from Microsoft do allow. But the new platform does not, though Microsoft executives argue that the platform's easy-to-use push notification and deft integration solve most of the multi-tasking challenges that mobile developers face.

But Jobs' real enthusiasm was clearly reserved for the embedded ad platform, called iAd, that will be part of the 4.0 release, based on the company's acquisition of Quattro. The goal, he and other executives repeatedly insisted, was "all about helping developers make money from advertising [and] to keep apps free" for iPhone users.