A technology reporter for Wired Magazine uncovered hundreds of convicted sex offenders on MySpace with a computer program that he developed, leading to one man's arrest.
There are more than 100 million users on MySpace, an online social networking service largely used by young people who post profiles and pictures of themselves, but it's also used by another group: sexual predators.
How many sexual predators use the site is a question that MySpace -- and sites like it -- have long contended is too difficult to answer.
But for Wired senior editor Kevin Poulsen that answer came quickly.
"There were some with records of crimes against children with a large number of children on their lists," Poulsen told ABC News.
Using names and addresses of convicted sex offenders on state registries, the editor designed his own computer program to cross-reference that information with profiles listed on MySpace.
Inputting close to 386,000 sex offenders from 46 states, Poulsen found thousands of possible matches.
Poulsen began looking at the site, combing through 7,000 profiles. Among them, he said, were 744 sex offenders with profiles on the site.
One particular sex offender stood out.
"In his MySpace profile, he had links to half a dozen kids -- all young boys -- and he was posting messages to their public comment boards of a sexual nature," Poulsen said.
The police stepped in, and posing as a teenager, investigators started sending him messages.
He took the bait.
"This guy was a registered level three sex offender with a profile on MySpace, actively looking for young boys to molest," said Sgt. John Cowie of the Suffolk County Police Department in New York.
The husband and father of five is now behind bars.
For its part, MySpace said it had been pushing for federal legislation that would require convicted sex offenders to register their e-mail addresses, even testifying before Congress about the difficulties in policing these types of sites.
Child advocates said this most recent case proved that MySpace and sites like it could do more right now.
In the most recent arrest, the convicted sex offender had been out of prison for just a year before his profile was on MySpace.
He is scheduled to be in court later this week.