Ned Bainbridge was the inventor of the Bainbridge variations; three notes in no particular key, played in ascending order. The effect of these notes when dropped in the middle of, say, a commercial jingle, was the same as a picture of a water fountain to someone dying of thirst.
Soundscape Weekly put forth a much simpler definition: must. A must hit the brain in a sneaky, indirect fashion, triggering a craving for whatever the jingle contained. The suddenly ubiquitous musts had an individual staying power of approximately four months, after which the buying public became desensitized to their lure.
Their creator, though eventually forgiven for unleashing the plague of noise upon the buying public, spiraled into a decades-long depression. He finally solved the mystery of inner peace during his stay at the Peaceful Oaks health sanatorium following his most recent nervous breakdown. There he noticed that the more local committants, deafened by years of construction work on the Dam road, were unaffected by his siren song. He excused himself upstairs and took a pencil to each ear. What met the public in the years after that was a smiling, apologetic man, adept at reading lips.