Facebook users have been puzzled by a disturbance in their feeds. Strange pictures with bold, funny phrases superimposed over them? It's happened: Old people on Facebook have finally discovered the image macro.

Slate writer Farhad Manjoo notes that he and his Slate colleagues have noticed an uptick in so-called "image macros"—pictures with words superimposed on them—streaming around Facebook. He singles out one image macro about Kim Kardashian and gay marriage (above) in particular. Instead of pictures of peoples' babies and dogs, Manjoo has been noticing Facebook pictures that are "more political, they're less intimate, and they're more calculated-many seem designed to become viral hits, and many do become viral hits."

Anyone who uses the internet for more than Farmville should be familiar with the image macro. As Manjoo notes, the phenomenon been around forever—it's a good candidate for the grandaddy of all internet memes. First made famous by LolCats, which sprung from 4chan's chaotic /b/ board around 2006, the image macro has diversified in recent years into memes like Scumbag Steve, Hipster Little Mermaid.

Manjoo cites a number of developments as explanations for why these memes are suddenly taking off on Facebook, like the site's new algorithm and look, and they're generally plausible.

But there's an obvious reason why it took so long for Facebook users to figure out image macros: Facebook users are old—their average age is 38—and old people are the last to learn about anything, online or off. Internet culture is a youth culture, and the image macros that eventually bubble up to Facebook were launched by 16-year-olds on Tumblr or 4chan. Old people discovering image macros through Facebook is a lot like old people discovering the Arcade Fire through NPR.

Facebook's already sucked up large portions of the internet and processed it into a thin mush palatable to old people (and the corporations they run). It was only a matter of time until it did the same thing to memes.