The Utah Attorney General, along with 42 other states, signed an agreement Thursday with Craigslist to reduce inappropriate content and illegal activity on the site.

According to a news release, the agreement is intended to regulate the erotic services section of the Web site to reduce problems with postings. Craigslist will now attach tags to the erotic services section that will help parental screening software and digital tagging will be used to identify and eliminate pornography and criminal activity.

"This agreement uses both the law and technology to try and stop prostitution, child abuse and human trafficking," said Paul Murphy, spokesman for the attorney general's office.

Murphy said the attorney general, Mark Shurtleff, has tried to use technology to end child abuse with programs such as www.NetSmartz.org and Web Wise Kids. The agreement will help protect children with a search technology developed by Craigslist to assist agencies in identifying missing persons, children and human trafficking victims.

Technology may also be put in place to block inappropriate image uploads and filter code words for illegal activity. Murphy said Craiglist will be requiring erotic services posters to submit phone numbers and a credit card number, which will provide a trail to those committing crimes.

According to the news release, Craigslist has committed to sue 14 software companies that charge a fee to help erotic service ad posters circumvent a Web site's defenses against inappropriate content.

Murphy said although agreements have been made with Craigslist and other social networking sites like MySpace, parents still need to take an active role in their children's Internet use.

"I still think the best protection is for parents to know what their kids are doing on the Web," he said.

As part of Craigslist's agreement with attorneys general around the country, anyone who posts an "erotic services" ad 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.

Jim Buckmaster, Craigslist's CEO, said the deal will allow legitimate escort services to continue advertising, while providing a strong disincentive to companies that are conducting illegal business.

"We don't view it as a penalty, we view it as raising the accountability," he said. "A legitimate business should have no problem with that. They should have no problem providing a phone number or credit card credentials."

Police across the country have been arresting people for using Web sites like Craigslist to advertise the sexual services of women and children.

"The criminals engaged in the sexual trafficking of children no longer parade them on the streets of America's cities," said the National Center for Missing and Exploited Children's chief executive, Ernie Allen. "Today, they market them via the Internet."

Over 40 states along with Washington, D.C., the U.S. Virgin Islands and Guam joined.

• The Associated Press contributed to this report