Beware of ads that use inaudible sound to link your phone, TV, tablet, and PC
Found on Ars Technica on Saturday, 14 November 2015
The ultrasonic pitches are embedded into TV commercials or are played when a user encounters an ad displayed in a computer browser. While the sound can't be heard by the human ear, nearby tablets and smartphones can detect it.
The officials said that companies with names including SilverPush, Drawbridge, and Flurry are working on ways to pair a given user to specific devices. Adobe is developing similar technologies.
Same advertisers tell us not to worry and that adblockers are evil and bad. Now we need soundblockers too. Or at least those who own mobile devices do (what also makes you wonder why a microphone is accessible like that for surveillance).