From 1925 to 1963, a brushless shaving cream called Burma-Shave became a ubiquitous and much-loved part of the American scene—not because of the product itself, but because of the roadside signs that advertised it in the form of humorous poems. Motorists in 43 states enjoyed slowing down to read six signs spelling out the latest jingle, always culminating in the Burma-Shave trademark. A typical example might be "PITY ALL /THE MIGHTY CAESARS /THEY PULLED /EACH WHISKER OUT /WITH TWEEZERS /BURMA SHAVE." The inspiration of Burma-Vita, a family-owned business in Minneapolis, the signs caught the public fancy with their refreshing "soft sell" approach. The uniqueness of the venue was another plus, and in time the Burma company took to offering jingles that promoted highway safety and similar public services—still finishing off, however, with that sixth Burma-Shave sign. Even the public itself was eventually invited to help create the jingles. The...