"Still, it’s interesting to know how these ad exposure estimates are calculated. The oldest such estimate is the one cited by David Shenk in Data Smog. His figure comes from a figure cited in Alvin Toffler’s 1971 book Future Shock. Toffler’s figure came from a conference speech that cited a number calculated by Bill Moran for use in that speech (delivered by his boss) when he was running the research function at Y&R. I know this because I am a friend of Bill’s and he has related this story to me. Bill made a simple calculation. He simply conducted a thought exercise and went through the typical day for a typical person in a typical American big city in the 1960s. How many times would such a person be exposed to some sort of ad, logo or promotion? He came to around 500. It’s that simple, and that’s where this early figure comes from.
Note what is being calculated here. Not the number of ads people pay attention to, but the number of ads that people might pay attention to. It’s exposure opportunities. Obviously, we live lives nowadays in which ever more of the white space around us is crowded with ads. Thus, we have many more opportunities for ad exposure."
Dissecting Advertising Clutter, Part I
Advertising Clutter in 1759