phreaking

Lately the term “dog-whistle” has taken on a purely figurative meaning for veiled code words that a signals a political response to those in the know, however, apparently marketers are adopting a very literal feature outside of the human range of hearing to gather and spread demographic information about potential consumers without their knowledge—with potential for much more invasive acts.
Though the method is comparatively an indirect one, it made me think of the subliminal messages embedded in movies to make people salivate and seek refreshment—and then perhaps as a closer parallel was the earlier experimental techniques of phreakers, playing a sequence of tones into headsets to commandeer telephone networks and make free long-distance calls. There’s surely nothing savoury in ultrasonic hacking and while the big telecoms may have seen nothing redeeming in “toll fraud” that undercut their profits, the founders of Apple and other industry luminaries got their start in this community.