Blake Ross, Facebook’s director of product, recently announced he’d be leaving the company. He posted a goodbye letter on his profile page saying, in essence, that he was leaving the company because youngsters no longer think the social network is cool. While there was an air of humor to his post, it also had some truth to it. He’s since taken down the letter, claiming it was posted publicly by accident.

Ross was speaking about Facebook’s annual 10-K report, in which it admitted that it might be losing some “younger users” to “other products and services similar to, or as a substitute for, Facebook,” reports The Verge.  “Teens are often an accurate barometer for what’s cool and what’s next, and recent rumblings seem to indicate teens are moving on. Telling your colleagues that teens are no longer into your product is far from an Irish goodbye.”

“I think it has less to do with kids consciously looking for ‘the next big thing’ than Facebook just no longer being a space that serves them,” says Laura Portwood-Stacer, author of “Media Refusal and Conspicuous Non-Consumption: The Performative and Political Dimensions of Facebook Abstention.”

“I think kids are less self-conscious about trying to be cool than marketers would like to think,” she said.

Regardless of whether they’re looking for it or just happen upon it, their next big thing might be Tumblr. They want more privacy and less bragging and can find it there. According to Adam Rifkin in a TechCrunch column: “Teenagers, amusing images, sharing only with trusted friends? In some ways, Tumblr is actually Facebook 2.0!” And “some data suggests that Tumblr may have already eclipsed Facebook as the most popular social network among 13-25 year-olds,” writes The Verge.

And again, as privacy becomes a rising concern of the younger generation, apps like Snapchat have emerged, in which users can send private photographs to friends. “In the age of the dox — where a sense of online privacy is very sacred, being able to communicate without leaving a permanent record is empowering. Whereas photos on Facebook last forever, photos on Snapchat typically last about ten seconds,” according to the article.

“Mark Zuckerberg’s baby is still a long ways off from the precipitous decline of Myspace, but the data and the details gathered from teens show Facebook needs to be nimbler than ever to stay relevant to the next generation,” concludes The Verge.