Stoobalou writes with a story that got started earlier this month when iPhone users in the US and the UK noticed that their phones seemed to be sending large data bursts via 3G overnight. (Providers are ending unlimited contracts, so iPhone users are paying more attention to how much data they are using.) The discussions began on MacOSRumors and an Apple discussion forum. Thinq.co.uk makes this guess as to what is going on, but doesn't offer much in the way of substantiation: "The simple fact of the matter is — as far as we can tell — that the iPhone's push notifications and other small transfers of data are totted up throughout the day and the total for all of those notifications is added up after dark and sent to your airtime provider while your phone is sleeping. If these tiny amounts of data were individually listed your bill would probably be the size of a telephone directory. The reason it is using the 3G network rather than Wi-Fi is that all iPhones up to and including the 3Gs turn off Wi-Fi push functionality while the phone is in sleep mode, in order to preserve battery life. The iPhone 4, incidentally, has better power management so will not need to do this."