Under the hood, TikTok is a fundamentally different app than American users have used before. It may look and feel like its friend-feed-centric peers, and you can follow and be followed; of course there are hugely popular “stars,” many cultivated by the company itself. There’s messaging. Users can and do use it like any other social app. But the various aesthetic and functional similarities to Vine or Snapchat or Instagram belie a core difference: TikTok is more machine than man. In this way, it’s from the future — or at least a future. And it has some messages for us.

Consider the trajectory of what we think of as the major social apps.

Instagram and Twitter could only

take us so far.

Twitter gained popularity as a tool for following people and being followed by other people and expanded from there. Twitter watched what its users did with its original concept and formalized the conversational behaviors they invented. (See: Retweets. See again: hashtags.) Only then, and after going public, did it start to become more assertive. It made more recommendations. It started reordering users’ feeds based on what it thought they might want to see, or might have missed. Opaque machine intelligence encroached on the original system.

Something similar happened at Instagram, where algorithmic recommendation is now a very noticeable part of the experience, and on YouTube, where recommendations shuttle one around the platform in new and often … let’s say surprising ways. Some users might feel affronted by these assertive new automatic features, which are clearly designed to increase interaction. One might reasonably worry that this trend serves the lowest demands of a brutal attention economy that is revealing tech companies as cynical time-mongers and turning us into mindless drones.

These changes have also tended to work, at least on those terms. We often do spend more time with the apps as they’ve become more assertive, and less intimately human, even as we’ve complained.

What’s both crucial and easy to miss about TikTok is how it has stepped over the midpoint between the familiar self-directed feed and an experience based first on algorithmic observation and inference. The most obvious clue is right there when you open the app: the first thing you see isn’t a feed of your friends, but a page called “For You.” It’s an algorithmic feed based on videos you’ve interacted with, or even just watched. It never runs out of material. It is not, unless you train it to be, full of people you know, or things you’ve explicitly told it you want to see. It’s full of things that you seem to have demonstrated you want to watch, no matter what you actually say you want to watch.