AshleyMadison.com describes itself as "an online dating service for people who are married or attached." The site's president, Noel Biderman, has been dubbed "The King of Infidelity" and drawn heat from religious groups. His business is booming and Biderman told OnMilwaukee.com that he is not trying to break up marriages, but to serve a market that already existed. For proof, he points to nearly 4 million users.