Based on a recently published patent application, Facebook could one day use ads on television to further violate your privacy once you’ve forgotten about all those other times.
The patent is titled "broadcast content view analysis based on ambient audio recording." It describes a system in which an "ambient audio fingerprint or signature" that's inaudible to the human ear could be embedded in broadcast content like a TV ad. When a hypothetical user is watching this ad, the audio fingerprint could trigger their smartphone or another device to turn on its microphone, begin recording audio and transmit data about it to Facebook.
Another ad-tech-privacy nightmare in making?