Your iPhone knows what you did last summer. Ever since Apple released iOS4, a secret file has been storing your movements. It works by triangulating your cell signal instead of the GPS. It's far from accurate. However, it does show the general vicinity of your travels. The scary part is how easy it is to access this information. Programmer and ex-Apple employee Pete Warden has developed a Mac OS app to access the data. It shows everywhere you've visited as a collection of dots on a map.

For it to work, you need iOS 4 installed on your iPhone or iPad 3G. During the brief three-month period I had it on my iPhone 3G, it shows the general areas I've travelled to. In some cases it's spot on, in others it's miles off.


Regardless of the accuracy, it's a serious privacy concern. Apple doesn't appear to be collecting or using this data in any way. However, they won't say why they're doing it. It's stored only on the phone itself and any computer you synced it to. This kind of information has potential benefits for law enforcement. We've all seen them do it on CSI. This information could be a huge advantage for darker elements too: stalkers, overzealous cops, lawyers, shady government agencies, and private detectives.