TIL TVs emit a tone during ad breaks that are inaudible to humans but that smartphones are listening for; now corporate entities can link the tv & phone as belonging to the same person. It means govt entities can play a tone thru the TV & ping all the phones in the room, identifying the whole group.

https://ift.tt/2pXit4m via /r/todayilearned https://ift.tt/2mmrTay