The price we pay for the new strategies in database marketing that closely track desirable customers, offering them benefits in return for personal information.

Joseph Turow, called by the New York Times probably the reigning academic expert on media fragmentation, is Robert Lewis Shayon Professor and Associate Dean for Graduate Studies at the Annenberg School for Communication, University of Pennsylvania. He is the the author of Breaking Up America: Advertisers and the New Media World, among other books, and the editor of The Wired Homestead (MIT Press, 2003).