It may be the world's oldest profession, but prostitution is using some 21st-century tricks. The prostitution scandal involving New York Gov. Eliot Spitzer lays bare some of the inner workings of modern-day sex work: text messaging to clock in the client, electronic fund transfers, a Web site featuring color photos, prices and rankings. There's always been a distinction between indoor and street-level prostitution, and advances in technology have increasingly separated the two, said Ronald Weitzer, author of "Sex for Sale: Prostitution, Pornography and the Sex Industry." Not only can prostitutes and escort services now run more efficient businesses, but they...