One of the biggest weaknesses of Apple's iOS remains notifications. These are bits of information, like an incoming text messages or a hot news alert from the New York Times app, that you might want to know about and act on immediately. On the iPhone, notices appear one at a time in the middle of the screen and lock you out of everything else until dismissed. You must then choose either to dismiss the notice permanently or go right to the app that sent it. There's no option to delay or deal with one notice but not another.
Rumors that Apple is acquiring the maker of an existing notification improving app, possibly Boxcar, has pundits predicting a rapid overhaul of iOS notices. But don't hold your breath. Last June, Apple re-hired Rob Dellinger from Palm to improve notifications and despite several iOS updates, no improvement yet. The deeper problem may be that improving the notification system requires an overhaul of iOS's limited multitasking abilities.
Competitors have the better offerings in this area of smart phone development. I'm a fan of Andriod 2.3's notices, which appear initially only as icons in the top status bar. A swipe pulls down a full list of all the notices. Click on any one and go to the appropriate app. A lot of people also like Palm/HP's WebOS notices which slide in as a small banner with lots of info and then slip away for later retrieval.