iPhone OS 4: multitasking, tentpoles, app folders, Game Center, iAd -- okay, maybe you weren't all that excited about iAd -- seemed destined to hit the iPad this summer. Surely, right? Instead, rather than finishing with his usual "one more thing" flourish today, Steve Jobs just left a stunned audience with the terse statement that Apple will be "bringing OS 4 to the iPad this fall." That's like... a whole different season from the new operating system's release. Why Steve, why?