It has been speculated that the next iPhone update will have better Twitter integration. With the soon-to-launch Twitter's own photo sharing service, some are speculating that we will see a "Post to Twitter" for photos. It looks like Apple may add a shortcut menu item to the camera that will allow the user to easily share their photos on Twitter right from their own iPhone.
There is even more speculation that with the oAuth for Direct Messages roll out, that Apple maybe integrating the phone calendar, iTunes music, or even allow for in-app social connectivity. This could potentially allow the iPhone user to send direct message calendar reminders, song recommendations, or game invites to other Twitter followers.