Thousands of software programs now offer cool new ways to chat and swap pictures. The most popular apps turn a hum-drum snapshot into artistic photography or broadcast your location to friends in case they want to meet you. Kids who use them don't need a credit card or even a cellphone, just an Internet connection and device such as an iPod Touch or Kindle Fire.

Parents who want to keep up with the curve should stop thinking in terms of imposing time limits or banning social media services, which are stopgap measures. Experts say it's time to talk frankly to kids about privacy controls and remind them - again - how nothing in cyberspace every really goes away, even when software companies promise it does.

"What sex education used to be, it's now the 'technology talk' we have to have with our kids," said Rebecca Levey, a mother of 10-year-old twin daughters who runs a tween video review site called KidzVuz.com and blogs about technology and educations issues.

More than three-fourths of teenagers have a cellphone and use online social networking sites such as Facebook, according to the Pew Research Center's Internet and American Life Project. But Facebook for teens has become a bit like a school-sanctioned prom - a rite of passage with plenty of adult chaperones - while newer apps such as Snapchat and Kik Messenger are the much cooler after-party.

Even Facebook acknowledged in a recent regulatory filing with the Securities and Exchange Commission that it was losing younger users: "We believe that some of our users, particularly our younger users, are aware of and actively engaging with other products and services similar to, or as a substitute for, Facebook," the company warned investors in February.

Educators say they have seen kids using their mobile devices to circulate videos of school drug searches to students sending nude images to girlfriends or boyfriends. Most parents, they say, have no idea.

A stay-at-home mom of eight kids in Burke, Va., Eileen Patterson said she used to consider herself fairly tech savvy and frequently spends time on Facebook. But she was shocked to learn her kids could message their friends with just an iPod Touch mp3 player. She counts nine wireless devices in her home and has taken to shutting off her home's Wi-Fi after 9 p.m., but she describes her attempt to keep tabs on her kids' online activity "a war I'm slowly losing every day."

"I find myself throwing up my hands every now and again," Patterson said. "Then I'll see something on TV or read an article in the paper about some horrible thing that happened to some poor child and their family, and then I try to be more vigilant."

Mobile apps refer to the software applications that can be downloaded to a mobile device through an online store such as Apple's iTunes. According to the Federal Trade Commission, there are some 800,000 apps available through Apple and 700,000 apps on Google Play.

Among the most popular mobile apps among kids is Instagram, free software that can digitally enhance photos and post them to your account online. Kids on Instagram whose parents closely monitor their text messages, Facebook posts or emails can also chat with their friends using the service. Their photos can also be shared on other social media sites such as Facebook, which bought Instagram last year.

Then there's Snapchat, among the top 10 free iPhone apps available. 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.

As with anything online, each of these services comes with caveats.

Snapchat acknowledges on its website that messages aren't guaranteed to disappear: Anyone receiving a textor photo can within 10 seconds capture a "screenshot," taking a photo of their device's screen, and save that image. Video also can be downloaded, although Snapchat says it alerts senders when material is saved.

Instagram is considered tame as long as kids adjust their 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 and these begin to circulate among their social circles.

Parents often hand their kids a mobile device without understanding exactly what it can do, said Dale Harkness, a technology director at Richmond-Burton Community High School in Richmond, Ill. He estimates that even without using social media services, the average high school student probably transmits some 150 texts a day.

"It's not anything that every parent and grandparent hasn't already seen," Harkness said. The problem, he adds, is that actions "get documented, replayed and sent around." He said that 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 humiliation of the victim and helped prove her case. The defendants and their friends had recorded the attack and later 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.

There are general security concerns, too. F-Secure, a cybersecurity company, said some new social networking services have become targets for spreading malicious hacker software and propagating scams.

In January, the FBI arrested a man in Los Angeles, Karen "Gary" Kazaryan, 27, of Glendale, Calif., on charges that he hacked into hundreds of social media and email accounts, including Facebook and Skype, and found nude photos and personal passwords that women had stored online. He allegedly used the photos to try to coerce women into disrobing for him via Skype and threatened to post their private photos to their Facebook accounts if they refused to comply, according to the indictment.

Online services also routinely collect personal data, such as a person's birthdate or the location of their phone, and they commonly share the information with third parties for marketing. While a new rule by the Federal Trade Commission this year is aimed at keeping advertisers from tracking kids younger than 13, most social media services require that a user specify he is at least 13, exempting the account from the tougher privacy restrictions.

Rep. Ed Markey, D-Mass., co-chairman of a House caucus on privacy issues, said legislation should give kids under 15 the right to delete photos or texts that wind up elsewhere online. The prospect, however, is unlikely in a Congress dominated by debates on federal spending and gun control, and raises practical questions about how such a law could be implemented or enforced.

"Nobody should be penalized for something they posted when they were 9 years old," Markey said.

Levey links her kids' devices to her iTunes account so she's aware of programs they install. She also requires that her kids make their accounts accessible to her and follow certain ground rules: protect your passwords, set privacy controls and never transmit inappropriate pictures or words.

A big hurdle for parents is overcoming the idea they are invading their kids' privacy by monitoring online activity, she said. In fact, she said, it can be the kid's first lesson that hardly anything online is private, anyway.

"If they want privacy," she said, "they should write in a journal and hide it under their mattress."