SEATTLE - Like many people his age, Rob spends a lot of time on the social networking site MySpace.com, but instead of chatting with friends, Rob is hunting pedophiles.

For security reasons, Rob asked us not to use his last name. In fact, he operates undercover on MySpace from his dorm room, posing as an underage girl, and the solicitations he gets are sickening.

"I saw some things that I really didn't want to see," he said.

Since November of 2006, Rob, who thinks of himself as an "Internet humanitarian," has tracked down some 6,700 profiles he believes are perverts, pedophiles and predators posing as teens themselves in search of young girls and boys.

He says the posts are obvious because they're go graphically sexual in nature.

"And then they say 'Oh, I'm bisexual, looking to trade nude pics' and they're really a pedophile and they're trying to solicit pornography from young kids," he said.

He reports them directly to MySpace security officials, who then delete the profiles.

Rob says he started his crusade after he was targeted on MySpace by a suspected predator.

"I looked through his friend list - found a lot of kids that shouldn't have been on there because they were underage, some other pedophiles and I was like wow this is a situation that needs to have something done about it," he said.

And even with nearly 7,000 profiles shut down, Rob says he's still astounded by the sheer volume of people on the site who are looking for child porn or to have sex with children.

The National Center for Missing and Exploited Children reports that one-in-five children are sexually solicited on-line.