Now TikTok wants you to turn your phone sideways

• After popularizing vertical videos, TikTok is now trying to encourage horizontal ones, too.
• It's promising to increase views for some creators who submit horizontal videos.
• The plan is a reminder that platforms often try to change user behavior with algorithmic incentives.

TikTok is an enormously popular video platform. Which means the way TikTok has taught people to consume video — holding their phones upright — is enormously popular.

Now, TikTok would like you to turn your phone sideways. At least some of the time.

TikTok has started asking some users to submit videos designed to be viewed horizontally. To make them work, you click on a "full screen" button and turn your phone. TikTok is telling creators that if they submit horizontal videos, the platform may "boost" their views.

Horizontal videos aren't new for TikTok. I periodically see them on my feed, but in my experience, they have exclusively been clips of movies and TV shows — something TikTok says it doesn't want people to post, because copyright.

But now it's asking video-makers to make stuff specifically for the format.

What's TikTok thinking? The internet's leading theory is that, for some reason, TikTok is "trying to be like YouTube." Which would be ironic now that YouTube is spending a lot of effort trying to promote YouTube Shorts — its horizontal TikTok clone.

I also wonder if this is an effort to get more content that will play well on an actual TV — an ambition TikTok has held for a long time but has yet to really figure out. Least compelling theory: It's an homage to Go90, a terrible, expensive, and now-canceled plan Verizon tried years ago to become a video hub. I've asked TikTok for comment.

The bigger picture — pun intended! — is that this is yet another reminder that the stuff that shows up on big internet platforms like TikTok, YouTube, and Instagram doesn't just show up there because users want to put it there. The platforms routinely try to change what's there using a combination of algorithmic carrots and sticks aimed at content creators.

TikTok, for instance, is also trying to get people to use its shopping feature and is boosting views for people who use that to sell literally anything.

That doesn't mean those incentives will last: For some time, YouTube was encouraging creators to post videos that ran 10 minutes or more but is now focusing attention on short clips (see, again: YouTube Shorts.) Way back in 2016, when Facebook thought live video was a good idea, it was literally paying outlets like The New York Times to make live video (at one point, the Times had team of 7 people working on these things).

So, sideways TikToks may or may not become a thing. But if they do, they won't have happened on their own.