Then there's Snapchat, among the top 10 free iPhone apps. Snapchat lets a user send a text, photo or video that purportedly self-destructs within 10 seconds of being opened — or warns a user if the recipient takes steps to quickly capture it for posterity before it disappears.
Kik Messenger also allows unlimited texting for free and effectively offers anonymity to users.
Snapchat acknowledges on its website that messages aren't guaranteed to disappear: Anyone receiving a text or photo can within 10 seconds capture a “screenshot,” taking a photo of their device's screen, and save the image. Video also can be downloaded, but Snapchat says it alerts senders when material is saved.
Instagram is considered tame as long as kids adjust privacy settings to limit who can see their photos and don't post nudity, which could subject them to child pornography laws. But Levey said many parents don't know their kids are using Instagram until there's trouble, usually when kids post inappropriate photos at parties, which begin to circulate in their social circles.
Parents often hand their kids a mobile device without knowing exactly what it can do, said Dale Harkness, a technology director at Richmond-Burton Community High School in Richmond, Ill.
The problem, he adds, is that actions “get documented, replayed and sent around.” He said students “forget how fast it moves and how far it goes.”
That was the case at Ridgewood High School in Ridgewood, N.J., where a male student allegedly took a screenshot of nude pictures sent to him by female classmates via Snapchat, then posted the pictures on Instagram. According to a letter to parents by the school district's superintendent that was later posted online, police warned students to delete any downloaded pictures or face criminal charges under child pornography laws.
In the Ohio rape case involving two football players, social media both added to the victim's humiliation and helped prove her case. The defendants and their friends had recorded the attack and joked about it on a video. The case didn't come to light until the girl read text messages among friends and saw a photo of herself naked.
And there are general security concerns. Cybersecurity company F-Secure said some social networking services have become targets for malicious hacker software and propagating scams.
Online services also collect personal data, such as a person's birth date or the location of their phone, and they commonly share the information with third parties for marketing. .
A big hurdle for parents is overcoming the idea they are invading their kids' privacy by monitoring online activity, Levey said. In fact, she said, it can be the kid's first lesson that hardly anything online is private.
“If they want privacy,” she said, “they should write in a journal and hide it under their mattress.”