It won't be long until the Feds have technology that grabs metadata from the tech in your car as you cruise down the road. I suspect their definition of "metadata" will be broad enough to include things like speed, rate of acceleration, latitude/longitude (if car is equipped with GPS, of course), etc. Seems crazy, except that most of us probably thought the idea of government backdoors in Google, Facebook, etc. to be "crazy" until very recently.
