Viral videos are fleeting; memes are even more ephemeral. One day, they’ll be all anyone is talking about. A week later, they’ve largely disappeared from your timeline. What the YouTube "Rewind" video does each year is collect them all in one place—set to a soundtrack of the year’s most popular music on the site and starring YouTube's biggest stars. It's a bizarre mix of everything you’ve already forgotten from the year, mixed with the things you can't erase and people whose faces you may or may not know. And in many ways, it's the Internettiest thing possible.

This year, that mix means that the girl from the Silentó’s "Watch Me (Whip/Nae Nae)" video dances in the same clip as Karlie Kloss, or a bunch of YouTubers from Latin America rock Left Shark costumes and flaming guitars like that guy in Mad Max: Fury Road. There's also, of course, a reference to Drake’s "Hotline Bling." And #PizzaRat. And The Dress. T-Pain even shows up—because there’s a sort of Rewind-within-the-Rewind that looks back at memes from previous years. (Hello, "I'm On a Boat" and Double Rainbow Guy!)

People like to say that putting YouTube celebs like Tyler Oakley and GloZell next to late-night hosts like Jon Oliver and James Corden proves that, as YouTube’s head of culture Kevin Allocca told AdAge, the line between mainstream culture and YouTube culture is "almost nonexistent." That’s true insofar as more people now (maybe) know who Tyler Oakley is, but there are still dozens of people in this video who will be total strangers to most people.

What really blurs the line is the memes, almost none of which were originally birthed on YouTube. Instead, they're from traditional media or other social platforms: Left Shark from Katy Perry’s Super Bowl show, or "Carpool Karaoke" from The Late Late Show. However, thanks to the substrate of of tribute and reaction videos that nourishes so much of YouTube, those memes ultimately come to rest in some form on the video site, where they coexist with people like PewDiePie. It’s not that YouTube celebs have gone mainstream—though Grace Helbig (also in this video) getting her own show on E! is a step in that direction—it’s that there is no mainstream now, just a series of tributaries that we occasionally dip our toes into.

Think of it this way: No one can ever look at all of the Internet. (We’ve tried.) But that’s kind of the beauty of it. Some people have seen Sia's "Elastic Heart" video, others have seen #PizzaRat, and a sliver in a Venn diagram would show a group of people who have seen both. Same with Justin Bieber’s "What Do You Mean?" and Flula Borg, who was a YouTube sensation before showing up in this summer's Pitch Perfect 2. Culture is everywhere now, and eventually it floats through YouTube, where Rewind catches it all in one place; the year-end video, essentially, is the lint trap of the Internet. Much like reading the Internet, you don’t have to get every reference—no one expects you to anymore—but they’re all there if you want to send yourself down a Google rabbit hole. In other words, "Rewind" is just what we do on the Internet—in video form.

The YouTube Rewind video works because it’s like CliffsNotes of facts that you’ll never be quizzed on. It’s just there to remind you of what you forgot earlier this year and teach you about the things you missed. It’s Cultural Literacy Lite. Learn it now—it may not matter in 2016.