Story highlights Facebook acknowledges that teen users are becoming less active on the site

Newer social tools like Snapchat, Instagram and Vine are picking up steam instead

Surveyed teens said "drama" and the presence of adults have cooled them to Facebook

But teens who don't use Facebook as much don't close their accounts

Nicole Uvieghara is only 18, but that's old enough to remember the good old days on Facebook.

"I used to log in to Facebook every day," said Uvieghara, a Murrieta, California, native and freshman at Arizona State University. "Now, I go, like, once a week. On my news feed, I rarely see posts from my friends and I have not posted things on my wall in the past year."

Her experience isn't unusual. Teens are cooling on Facebook, a trend suggested by recent research and acknowledged, this week by Facebook itself. The shift was confirmed time and time again in e-mail and phone interviews with dozens of teens and their parents in CNN's reporting of this story.

While the social-networking juggernaut continues to chug along among adults, boasting more than 1 billion active users, younger users are flocking to newer, and arguably hipper, networking tools.

Sherman Watson of San Francisco said he's noticed a dip in Facebook use by both his 18-year-old son and the younger employees at the retail store he manages.

"I think his generation, and definitely the younger ones, view Facebook as boorish and -- let's face it -- something that their parents use," Watson wrote in response to a Facebook post seeking thoughts on the issue. "Funny how history repeats itself in this regard."

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Instead, he said, mobile apps like Facebook-owned Instagram, and Vine, Twitter's video tool, are where teens increasingly go to share.

For the first time this week, Facebook confirmed the trend is real.

"We did see a decrease in (teenage) daily users, especially younger teens," Facebook Chief Financial Officer David Ebersman said Wednesday during a quarterly earnings call.

It was just months ago that Ebersman called the decline of teens using Facebook an "urban legend," saying they were active on more sites, but not cutting back on their Facebook visits. CEO Mark Zuckerberg added that it "just isn't true" that Facebook has a teen problem.

But even then, there were signs of a slide.

In May, a survey by the Pew Internet & American Life Project included focus groups with teens who said their enthusiasm for Facebook had waned. They cited the increasing presence of adults on the site, as well as stressful "drama" among friends.

The survey showed use of Twitter among teens jumping from 11% to 26% between 2011 and 2012. Teen Facebook use, on the other hand, remained essentially flat. (Albeit at a massive 93-94%). Instagram use, which wasn't measured in the 2011 survey, was at 11% in last year's.

Most teens in the focus groups said they kept their Facebook pages, but had migrated to new tools and sites for most of their activity.

That sounds about right to Alex Hager, 16, a high school junior in Darien, Connecticut.

He said the rise of new networks -- video-clip app Snapchat and messaging tool KiK are other popular choices -- has met a desire among his peers who would rather communicate directly than broadcast to hundreds of Facebook friends.

"Everybody was Facebook friends with everybody in my grade, regardless of how well they knew each other," he said. "This meant that whenever somebody publicly interacted with somebody else in your grade, you would see it instantly."

Now he'll post things like the YouTube videos he and some friends make about his school's sports teams to the site, but said "I rarely ever use Facebook to post statuses or photos anymore."

While Facebook has downplayed the importance of the trend, the site simultaneously appears to be taking steps to address it.

Earlier this month, Facebook changed privacy settings for teens , allowing them for the first time to make their profiles public. Teens may now also turn on the site's "Follow" feature, which allows people to view their posts whether the teen has accepted a friend request from them or not.

Teens who join the site will still have their settings default to "Friends Only" and, if they switch to public, they will get pop-up warnings explaining what having a public profile means.

The public nature of Twitter has been appealing, teens say, because they can build bigger followings and interact with people up to and including their favorite celebrities. The same goes for other apps.

"It makes you feel relevant and wanted because of the number of followers a person can have and the likes you can have on your photos," Uvieghara said, describing Instagram.

She said she doesn't think her Facebook use will ever pick back up. Hager, meanwhile, wasn't so sure.

His thoughts might provide a ray of hope for Facebook . Because, given enough time, the teens who are fleeing Facebook become the adults who still flock to it.

"I hope that my peers continue to use Facebook in the future," he said. "It will be a valuable means of staying in touch as we move on to college and careers."