By the middle of the 20th century, Sears, Roebuck had come to town as the nation's largest retailer, with stores that defined many towns' downtowns. But in Bentonville, Ark., Sam Walton had an idea for bigger stores on the outskirts of towns. Sears has become a casualty of Wal-Mart's retailing revolution.
Today new mothers sign up at Amazon Mom for regular deliveries of diapers. This is a 21st-century permutation of an innovation in long-distance commerce that began in 19th-century Chicago.
Creative destruction continues in the digital age. After 244 years - it began publication five years before the 1773 Boston Tea Party - the Encyclopaedia Britannica will henceforth be available only in digital form as it tries to catch up to reference Web sites such as Google and Wikipedia. Another digital casualty forgot it was selling the preservation of memories, a.k.a. "Kodak moments," not film.