From 1956—Advertisers Snooping on Private Media Consumption

As television broadcast advertising took off in the 1950s U.S., advertisers had no to way to estimate how many people were viewing the channels on which they were buying time other than spotty and unreliable samplings such as Nielsen ratings.

Poll-o-meter promised to provide broad-based and unbiased data by driving vans equipped with a large antenna and monitoring equipment through neighbourhoods and, by picking up leakage from the local oscillators in television sets emitted through the outside antennas on houses (which almost all sets required in the era), determine and count the channel to which each set was tuned.

One of the more remarkable parts of this snapshot of a forgotten time is how the housewives they show reacted to having their day interrupted by telephone and door-to-door snoopers asking what TV programs they were or had recently watched. One trusts that anybody trying this today would compile, instead, a comprehensive database of anatomically improbable acts they were suggested to perform or, in Texas, the many varieties of well-deserved internal ventilation trespassers and busybodies might receive instead of the information they were seeking.