The 1993 release of Mary-Kate and Ashley Olsen: Our First Video turned out to be a world-beater, topping the Billboard music-video charts ahead of all the adult rock heavy-hitters. That got BMG's attention, and the company agreed to do a series of videos with titles like You're Invited to Mary-Kate and Ashley's Sleepover Party. That series eventually expanded to dozens of titles in which the twins play detectives (The Adventures of Mary-Kate and Ashley: The Case of the Mystery Cruise, for example), give parties, talk fashion and boys, and dance and sing. Now distributed by Warner Home Video, the videos have sold more than 30 million copies.

The videos succeeded in spite of Mary-Kate and Ashley's demonstrably and, apparently, incorrigibly modest ability to dance and sing. They were better as actresses, showing a winsome sweetness and natural on-screen air that is unquestionably genuine, given that they have literally grown up in front of a camera. They were less successful with a second television series called Two of a Kind that didn't last out the 1998 season. Their feature films, starting with 1998's Billboard Dad, performed better, but Mary-Kate and Ashley weren't destined to find nearly as much success as entertainers - during the 1990s, at least - as their cornucopia of branded goods did in the marketplace.

Mary-Kate and Ashley's success as Martha Stewart-style purveyors of signature goods such as dolls and clothing is based largely on one thing - control. Thorne, and to a lesser extent the two girls, control if not every aspect of the products churned out by their branding machine, then at least far more details than a typical celebrity licensing enterprise. The usual celebrity trying to cash in on fame will happily and indiscriminately slap his or her visage on T-shirts, lunch boxes, blue jeans, and any number of other products. The deals will be made with companies that design, manufacture, and distribute the goods, with no more than after-the-fact approval from the celebrity.