Vermont and 39 other states have reached an agreement with the Web site Craigslist to crack down on ads for prostitution.
Under it, anyone who posts an "erotic services" ad on Craigslist will be required to provide a working phone number and pay a fee with a valid credit card. The Web site will provide that information to law enforcement if subpoenaed to do so.
Police across the country have been arresting people for using Web sites like Craigslist to advertise the sexual services.
The agreement between the states and Craigslist was joined by the National Center for Missing and Exploited Children.