You don't have to be paranoid or a criminal to imagine the various ways this information can be abused. Telecoms could make huge profits by selling your location data to marketers. Divorce attorneys, insurance companies, and employers all would love to get their hands on information about where you've been. The only thing keeping this stuff from being shared or sold are the ever-mutable privacy policies of the companies that collect this data.

For the past five years I've asked companies that collect location-based data what protections I have against my data being shared with third parties. The answer I have always gotten: Companies that store this data must comply with legal orders (so if the cops want this info, they can have it); there are no laws that give me control over my location data or even let me find out who else has it; and private companies are free to abuse this data but would be fools to do so because they'd lose their customers' trust.

Personally, I don't buy that last argument. Yes, they'd be fools. But some would do it anyway and make as much money as they could until the FTC eventually got around to suing them, probably five years after the fact. That's no protection at all.

I'm on board with Soghoian: We need laws that not only disclose who's watching where we go, but also giving consumers control over who else gets to know.

In the future, lawyers and the cops won't have to ask "where were you on the night of Dec. 4, 2009?" They'll know already, because they'll have your cell phone records in hand. Think about that, the next time you leave the house with your constant companion.