“What [advertisers] buy are the services of audiences with predictable specifications which pay attention in predictable numbers and at particular times to a particular means of communication [sic] in particular market areas.  As collectivities these audiences are commodities.  As commodities they are dealt with in markets by producers and buyers (the latter being advertisers).  The audience commodities bear specifications known in the business as “the demographics.” The specifications for the audience commodities include age, sex, income level, family composition, urban or rural location, ethnic character, ownership of home, automobile, credit card statues and social class.”

- Dallas Smythe [via: Radio Active: Advertising and Consumer Activism by: Kathy M. Newman]