Beware: Your Cell Phone Is Watching You

Your cell phone knows when you're sleeping, when you're awake, and whether you prefer air or land travel. German politician Malte Spitz recently took Deutsche Telekom to court to determine exactly how much it knows about his whereabouts, the New York Times reports. Data in hand, he saw that Deutsche tracked his coordinates at home, on the train, even on an airplane. “At any given instant, a cell company has to know where you are; it is constantly registering with the tower with the strongest signal,” one expert says.

Spitz was tracked whenever he checked his email, 35,000 times over a six-month period. Shoring up support for his cause by sharing the data on a public Google Doc and in German newspapers, Spitz helped move German courts to outlaw some invasive data retention policies, but he believes more regulation is needed. American providers, meanwhile, declined to spell out for the Times exactly what kind of information is kept on US customers or how it is used. They're not required to do so by law. (More cell phones stories.)