A new Pew Research study reports that Facebook continues to be the social media outlet of choice for American adults, with some 71 percent of online adults using the platform. That's up from 67 percent  in 2012. But while the adult audience for Facebook is still climbing, teens seem to be losing interest, according to the study, which was released Monday.

A academic who has been studying social networks in the United Kingdom recently wrote: "Facebook is not just on the slide, it is basically dead and buried" to 16-18 year-olds in that country. That's probably a bit hyperbolic, especially considering another recent Pew report showing that 94 percent of teen social media users had a Facebook profile. But even in that survey, the focus groups "expressed waning enthusiasm for Facebook," and researchers noted that just having a profile didn't mean teens used the platform the most.

Facebook's chief financial officer even acknowledged a downward trend in engagement in October, saying the site has seen a "decrease in daily users specifically among younger teens." And one of the reasons for this lagging interest? The increasing adult population on the site.

There's a helpful analogy to bars to be made about this situation. When there's a hot new watering hole on the scene, the hip young crowd comes out. But as word about the place spreads, it starts to attract an older clientele or, god forbid, tourists

Facebook is that once-hip bar. It created an aura of exclusivity by rolling out through college campuses before eventually opening up to the general public. But now everyone, their mom, and maybe even their grandma, is on it. And having your mom be able to see everything you do is sort of a buzzkill, especially for teens who are presumably working hard to keep some aspects of their social life guarded from their parents.

And like a social scene that migrates to the next hot stop once it has been discovered by the masses, teens are moving on to other networks. For instance, 24 percent of online teens now use Twitter as compared with 16 percent in 2011.

"Yeah, that's why we go on Twitter and Instagram [instead of Facebook]," one teen told Pew, explaining that her mom hasn't yet joined those networks. That leeriness of having their every action watched by authority figures may also contribute to teens' use of more superficially privacy-oriented services like SnapChat. Even if security flaws make the ephemeral nature of Snapchat somewhat illusory, for teens it still probably beats knowing mom is reading every comment they make.