We have long known that the iPhone will automatically check in and make data transfers, but just how much data gets transferred, and how is it accounted for on your bill?

That's the question that the ladies and gentlemen in the MacRumors forum have been asking for several days now. iPhone users have been going over their bills and noticing some very hefty data transfers. Multiple users on multiple carriers have checked out their bills and reported the same thing, large data transfers occurring late at night, often between 1 and 3 AM, when the user is not running any applications.

There are multiple theories circulating for why this happens. Some users suggest it's a total report of all data used during the day, others suggest that it's from multiple applications checking in and updating.

One good thing is that the transfers don't appear to be adding usage onto the bills of those on fixed-amount data plans, so no reports of extreme sticker shock as of yet. AT&T has been contacted by a few users, but so far no official word on what exactly is going on.

In the end, probably not a big deal, but either Apple or one of the telco partners should post an explanation. In the meantime, who doesn't love a good mystery?

18 Jun 2010