Maya Shelton-Davies knows her online audience.

Her Facebook friends and Twitter followers aren’t that interested in mundane complaints or what she ate for lunch. But a quip about the time she killed the spider on her bedroom wall by shooting a vitamin from her slingshot?

“People thought it was hilarious,” said Shelton-Davies, 16, from River Falls, Wis. “I got a bunch of ‘likes’ on it.”

Teenagers are sharing more than ever before on social media. Seventy-seven percent of teens who go online have Facebook accounts, while one in four are on Twitter. As the digital deluge grows, parents everywhere continue to fret about privacy, especially as it concerns their children. But new research shows teens themselves are surprisingly adept at managing the online boundaries between public and private, thanks in part to that age-old adolescent preoccupation with the opinions of others.

“Teens with larger friend networks on Facebook share a wider range of content with a wider range of people, but they are also more active ‘reputation managers,’ ” said Amanda Lenhart, a senior researcher with the Pew Internet Project and co-author of the study “Teens, Social Media and Privacy.”

Sixty percent of teens use privacy controls to allow only approved “friends” to see their Facebook profiles. Almost all of those friends — the average Facebook-using teen has 425 — are acquaintances from the real world, not the anonymous online strangers that parents fear. Within those online circles, as in high school hallways, there’s pressure for approval from peers.

The findings reveal the diligence with which teens tend to their digital lives.

Fifty-nine percent of teens said they had pruned online profiles by deleting or editing their own posts later. More than half had scrubbed friends’ comments from their profiles. Forty-five percent had removed their names from photos in which they’d been tagged by others. Profile pictures are chosen or discarded based on how many “likes” they garner.

Decisions about what to post, it appears, weren’t driven by what privacy settings allowed, but by what their friends would find interesting and “possible consequences imposed by adults,” said the study’s co-author, Sandra Cortesi, from the Berkman Center for Internet & Society at Harvard.

Shelton-Davies knows that her parents will review her Facebook and Twitter profiles.

Her dad, Joshua Davies, said the family talked about what was appropriate before she set up the accounts. Since then, he said, it’s been amusing to watch her online identity develop.

“Maya’s a writer and she’s funny,” Davies said. “She’s not careless about what she posts.”

Indeed, Shelton-Davies said her goal isn’t sharing her every move or daily thought, but developing a witty online persona.

“I think about what I post: If I were someone else, what would I want to see?” she said.

Teens who have grown up with online alter egos, first on MySpace and now Facebook, Twitter and other platforms, are keenly aware of ways to burnish those digital identities, said Shayla Thiel-Stern, an assistant professor at the University of Minnesota who studies youth and social media.

“In a lot of ways, they’re more sophisticated than we give them credit for,” she said.

Parents creeped out

The study highlighted one pronounced difference of opinion between teens and parents.

Just 9 percent of teens were “very concerned” about third parties, usually private businesses, harvesting data about them and their online behavior for marketing or other purposes. Among parents, 46 percent were “very concerned” about the practice.

Thiel-Stern chalked that divide up to some naiveté on the part of teens and broader generational differences.

“Younger people tend to see targeted marketing as a benefit to them,” she said. “Older generations probably find that creepy and annoying.”

Still, she said, the study makes clear that messages about online safety from parents and teachers have sunk in for most teens. Certainly, a few will make grave mistakes, but many more will socialize online without incident.

Ibad Jafri, 18, of Eagan, doesn’t post his phone number or address on his Facebook profile because, he said, “there’s no need for that information to be out there.”

He’s also careful about sharing strong opinions or anything that could be compromising in the future.

“A lot of it is about building an image,” Jafri said. “When you have 600 friends or so, you don’t share anything with them that you wouldn’t share with the world at large.”