That moment when we played with syntax

In That Way We're All Writing Now, Clive Thompson investigates the rise of a form of writing I'll refer to as the stand alone subordinate clause, often accompanied by an image, a sequential grid of images, an animated GIF, or a Vine.

One of the most popular forms is the “when you” subordinate clause:

Popular sub genres include “when your” and “when your ex,” but let your imagination roam and you will find yourself deep down many a rabbit hole.

Another popular form is “that moment when.” Here's one that functions also as a humblebrag, a more sophisticated instance of the form.

Searching Twitter for “that awkward moment when” is the new, low-fi form of America's Funniest Home Videos, which is ironic since the form defies any highbrow incarnations.

Thompson offers a couple explanations for the rise of this type of expression online.

1) It creates a little puzzle.
Grammatically speaking, what’s going on here is the rise of the “subordinate clause.” A subordinate clause isn’t a sentence on its own. As the name implies, it requires another sentence fragment to complete it, as with this example that McCulloch and I looked at on Yik Yak:
Usually you can quickly deduce what the missing part would be. Maybe it’s something like You, sadly, always know what to do when she’s holding a dog on her Tinder and you’re like, “cute dog.” Or maybe the full sentence that emerges in your head is more convoluted, like Nothing is more bittersweet than reflecting on the challenges of dating someone who is superficially attractive but owns a pomeranian and thus, you worry, has all sorts of dog/partner priority issues, which you can instantly intuit when you’re using a dating app and see someone when she’s holding a dog on her Tinder and you’re like, “cute dog.”
The point is, it’s up to you imagine the rest of the utterance. It’s like the author is handing you a little puzzle. Subordinate-clause tweets and Yik-Yak postings seduce us into filling out that missing info, McCulloch says. “Our brain has to work a little bit harder to figure out what it’s referring to, and so making that connection is very satisfying. It’s like getting a joke. You have to draw that connection for yourself a little bit — but because you can do it, it works really well.”
A historic parallel? The crazy, long chapter headings in 19th-century novels, which often were also dependent clauses, inviting the reader to imagine the rest of the baroque narrative. “In Which Our Protagonist Meets A Dashing Stranger,” McCulloch jokes. “The ‘in which’ is doing a very similar thing.”

The ordering of the best of these subordinate clauses is critical; the punch line needs to come at the end. Like a joke, the setup comes in the first part of the clause so the closing can knock the pins down with maximum effect.

I'm more partial to Thompson's final explanation, which isn't a reason as much as it is an observation of how much we tinker with syntax online.

What’s happening now is different. Now we’re messing around with syntax — the structure of sentences, the order in which the various parts go and how they relate to one another. This stuff people are doing with the subordinate clause, it’s pretty sophisticated, and oddly deep. We’re not just inventing catchy new words. We’re mucking around with what makes a sentence a sentence.
“Playing with syntax seems to be the broad meta trend behind a whole bunch of stuff that’s going on these days,” McCulloch tells me. And it goes beyond this subordinate-clause trend. Many of the biggest recent language memes were about syntax experimentation, such as the “i’ve lost the ability to can” gambit (which I wrote about a few months ago), or the gnarly elocution of doge, or the “because” meme. (Indeed, Zimmer points out, the American Dialect Society proclaimed “Because” the Word of the Year for 2013, largely because it had been revitalized by this syntax play.)
Why would we be suddenly messing around with syntax? It’s not clear. McCulloch thinks it may be related to a larger trend she’s identified, which she calls “stylized verbal incoherence mirroring emotional incoherence”. Most of these syntax-morphing memes consist of us trying to find clever new ways to express our feelings.

I consider these to be a formal type of internet expression just as haikus and sonnets are forms of poems. Just as genres of movies are constraints within which artists can focus their creativity, this form of social network post has its own formal conventions within which everyone can exercise their wit. As soon as the reader's eye spots the opening “that awkward moment” or sees a grid of images with giant text overlaid, their mind is primed for the punch line.