BOSTON -- With more and more teens sharing personal information online, parents need to be looking out for potential danger.

NewsCenter 5's Jim Boyd reported that popular social Web sites Facebook and MySpace are connecting millions, but among the "friends" are predators.

VIDEO: Teens Warned About Putting Personal Info. Online

Like most teenagers, Kayla Dias spends lots of time on the Internet, much of it communicating over social networks such as Facebook. Internet security expert Ted MacLean said there can be substantial benefit to using such sites, but it can also be risky.

"Fifty-five percent of teens have their own site online, and of those 80 percent of them include information like their name, photos of themselves," McLean said.

"Her school information was out there. Her hometown information was out there. Her activities and things like that were listed," Kayla's mother, Debi, said.

MacLean said a big mistake teens make is allowing the public to have access to the information on their sites.

"People see who your friends are and they say, 'You have a lot of friends in common with me, and maybe we can get to know each other or something?'" Kayla Dias said. "I'm pretty sure (my mom) looks at my profile at least every day when she's at work at least once."

Debi Dias said she found information on her daughter's page that could put her daughter at risk.

"I took my name off of it and I took my birth date and a lot of other stuff of that," Kayla Dias said.

MacLean said the Dias family is taking the right approach.

"It's really about parents having a conversation with their kids, talking about how to stay safe online, talking about what kind of information is appropriate to share on line and, really, understanding how they're using the Internet," he said.