Tumblr's teenage wasteland: Wait till Mom and Dad find out

Screengrabs of GIFs from one of the many Tumblrs dedicated to porn star James Deen — which are a lot dirtier when the pictures are moving.

Let's face it: Part of Tumblr's popularity is that it's been sort of a porn Facebook for teens. With Yahoo's purchase for $1.1 billion, it seems, that won't be going away. At least according to Yahoo CEO Marissa Mayer, who says Yahoo has no plans to mess with Tumblr.

Tumblr's unique charm combines the teen angst of Live Journal with the enforced brevity of Twitter, plus kitten GIFs! It's perfect for obsessives as well as those with short attention spans. It invites the anonymity of the old-timey Internet. It inspires running jokes such as blogs that start with "F*** yeah!" and single-topic blogs on specific sexual paraphilias shared with like-minded people who will never know your real name.

Related: Can Yahoo avoid 'screwing up' Tumblr and still make money?

You see, unlike Facebook, you don't have to log in to view posts and you don't have to use your name if you do. This is especially appealing given that Tumblr says, right in its terms of service, that it's perfectly OK with "Not Suitable for Work" content.

Hence, what people are calling "Tumblr's porn problem." The site is notoriously home to blogs by high school girls dedicated to porn star James Deen. And that's just the tip of the Tumblberg.

PrivCo, a company that researches privately held businesses, estimates that one in six Tumblr pages contain adult content. TechCrunch just reported that over 10 percent of the top sites on Tumblr are adult-themed. There are Tumblrs dedicated to very graphic GIFs grabbed from porn movies — both live action and animated, porn associated with particular professions or food products, even X-rated Tumblrs dedicated to cataloging Tumblr porn.

And porn is only part of the potential parental/shareholder/advertiser nightmare. While the site claims it's cleaned it up, there are still more than a few pro-anorexia "thinspiration" posts to be found, not to mention sites featuring "cutting" and other self-harm practices, for instance.

All of this is a byproduct of the kind of environment that kids thrive in, sharing what they wouldn't dare share on Facebook — not just because they're not allowed, but because their parents are on Facebook, too.

"It's just so weird. After hearing about the acquisition I got really upset. IDGAF when Facebook bought Instagram but Tumblr is/was sacred. It was always sacred," read one Tumblr post (which derived emotional emphasis from the acronym for "I don’t give a f***").

"Tumblr was the best kept 'secret' from tons of mainstreamers. Now what are we supposed to do?" wrote another user. "This site is like a second home, and the friends I've made here are a second family," wrote a third. "I don't know where go if the site dies. It just doesn't feel fair."

Will coming changes drive off Tumblr’s 300 million monthly unique visitors and 120,000 daily new account signups, and diminish its reported 900 posts per second? Or is the corporate acquisition of this particular pocket of youth culture enough to inspire an exodus? When, where and why Tumblr devotees will homestead another area of the Internet — or maybe take up a non-digital hobby — remains to be seen.

Meanwhile, anyone who's known the heartache of seeing a favorite indie band signed to a major label or were alive to see Facebook open its doors to everyone know exactly where disenchanted Tumblr users can go: Somewhere else.

Truth be told, Tumblr is pretty mainstream already. This is the site that birthed the Ryan Gosling "Hey Girl!" meme that even Ryan Gosling knows about. Talk about gentrification — the Tumblrs "Feminist Ryan Gosling" and "Look At This F***ing Hipster" are just two of several blog-to-book deals that started on the site.

Though it seems so very long ago, there was a time when the kids cherished Facebook in the same way, back in 2006 when there were dinosaurs and "My grandmother joined Facebook!" headlines were still fresh.

People complained, but Facebook went on to become the world's largest social network. It got the nickname "Mombook" even though the majority of its users are 18 to 29 years old, according to the Pew Internet & American Life Project.

Yes, the kids stayed, but even Facebook admits they're not as engaged as they used to be. In its April report to the Securities and Exchange Commission, Facebook stated, "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."

On Instagram, there are nearly twice as many teens as adults. Snapchat, too, is way more popular among teens. A survey of just over 1,000 people in two segments, teenagers and young adults 19 to 25, conducted in January by consumer research group Survata, revealed those unsurprising findings along with a bit of a coup: Despite being significantly smaller than Facebook, Tumblr was named the top social media outlet for 59 percent of the surveyed teens.

"Reblog if you hate our new stepfather Yahoo," read a post on the Doctor Who-themed Tumblr, "I Am Mr. Clever." "Stepmother," too, is being bestowed on Yahoo by Tumblr users, taking the disaffected stance of irritable teenagers.

Mayer implied the porn can stay. “I think the richness and breadth of content available on Tumblr — even though it may not be as brand-safe as what's on our site — is what's really exciting and allows us to reach even more users," said Mayer. In the same breath, though, she confirmed that there will be more advertising.

Stepparents can never win, but a surge of ads is nothing compared to a sudden drop in cool cache, or an increasing feeling that users' private conversations and online diaries are not quite so private anymore. Your parents may turn up or worse — be recommended to check out your blog by a well-intentioned algorithm. It’s just a matter of time before mom or dad find their way over, and that will automatically make everything uncool.

— Rosa Golijan contributed to this report.

Helen A.S. Popkin is Deputy Technology & Science editor for and TODAY. Follow her onTwitter and Facebook.