WASHINGTON — After Friendster came MySpace. By the time Facebook dominated social media, parents had joined the party, too. But the online scene has changed — dramatically, as it turns out — and these days even if you’re friends with your own kids on Facebook, it doesn’t mean you know what they’re doing.

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 said they have seen kids using their mobile devices to circulate videos of school drug searches or 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.”

Mobile apps refer to the software applications that can be downloaded to a mobile device through an online store such as Apple’s iTunes. 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..

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 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. 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.