That kind of approach works more often than parents would like to believe.

"There's no high school that's immune to this," Ken Cuccinelli, Virginia attorney general, said in a press conference unveiling the charges against Strom. "It demands increased vigilance by both parents and law enforcement into the activities that are occurring across those social media lines."

The FBI, which is often on the front lines of investigating these cases, has a tip sheet on its website to help parents protect their children on social networks.

The agency recommends that parents monitor their kids' online profiles and postings -- a controversial step in many households, but one the agency thinks is essential. It also recommends that parents educate their kids about how broadly the messages and photos they post online can spread. Teenagers don't always realize that they can't "take back" texts and images.

"I've talked to parents who say, 'Hey listen, my son has to set up my computer 'cause I just don't know,'" says the FBI's Bennett. "That's not an excuse anymore. You've got to know, because it's your child's life and their well-being depends on this."

Breaking free

Nina describes being raped, beaten with a pistol, and, once, locked in a closet for 24 hours. Beyond the physical threats, shame kept her from running away.

"I didn't want to tell my parents, 'Ya know, this is what I'm doing,'" she says. "How am I going to explain that to my father? That wasn't an option for me at all."

Nina bounced through a series of different pimps, eventually ending up "working" for a trafficker who took away her ID and forced her to dance -- and more -- at strip clubs and in hotel rooms.

A massive raid by local police and the FBI shut down his operation about a year ago. Without that, Nina says she could still be working for him today. Advocates at Fair Girls are helping her rebuild her life. She's planning to begin college in the fall.

Both Nina and Lisa still maintain accounts on the social networks on which they were recruited, mainly to keep in touch with friends and family. Both receive daily messages from pimps.

They no longer respond.

"I want to get my life together," says Lisa, who is working to earn her GED. "If I start school, I probably won't have a Facebook page."