Location data

“Only one person makes that trip: Lisa Magrin, a 46-year-old math teacher. Her smartphone goes with her. An app on the device gathered her location information, which was then sold without her knowledge. It recorded her whereabouts as often as every two seconds, according to a database of more than a million phones in the New York area that was reviewed by The New York Times. While Ms. Magrin’s identity was not disclosed in those records, The Times was able to easily connect her to that dot.”

Source : Your Apps Know Where You Were Last Night, and They’re Not Keeping It Secret – The New York Times