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In 1978, ad executive Donald Gunn took a year off from the fast paced world of advertising to sit down and catalog what would become the 12 types– or “master formats”– of television advertisement. Among them are the Demo (a favorite of late-night infomercials), the Comparison (”The new 3 Series kicks Mercedes ass because…”), and my all time favorite, the Ongoing Character (think Taco-Bell dog or Geico Cavemen). While a pretty simple concept on the whole, Seth Stevenson of Slate zests things up a bit in this video tour.