A substantial body of laws and regulations governs advertising. Under U.S. law, advertisers must
not make false claims, such as stating that a product cures something when it does not. They must
avoid false demonstrations, such as using sand-covered Plexiglas instead of sandpaper to demonstrate
that a razor blade can shave sandpaper. It is illegal in the United States to create ads that have
the capacity to deceive, even though no one may actually be deceived. A floor wax advertiser can’t
say the product gives six months’ protection unless it does so under typical conditions, and the
maker of a diet bread can’t say it has fewer calories simply because its slices are thinner. The challenge
is telling the difference between deception and “puffery”—simple exaggerations that are not
meant to be believed and that are permitted by law.