X is expanding access to its new vertical video ads, which are displayed within its dedicated video feed, that’s activated when a user taps through on a specific video clip in-stream.

Which is not how you would assume that many people are watching video in the app, given that the majority of X’s usage is in the main feed. But apparently, that assumption would be incorrect, because X says that 100 million users now engage with vertical video in the app every day.

As per X:

“X is becoming a video-first experience, with video now part of more than four out of five user sessions, and video views growing at an average rate of 35% year over year. Today, we’re expanding Vertical Video Ads to all advertisers globally, enabling a full-screen, sound-on advertising experience on X’s fastest-growing video surface.”

Now, how, exactly, X can call itself a “video-first” platform when it doesn’t open to a video feed is another question. But maybe that’s coming too.

X says that, based on testing, Vertical Video Ads are the most engaging ad format that it’s ever released, though whether that incorporates the history of X and Twitter, or just X, is unclear.

“We’ve observed that X users are 7X more likely to engage with an ad in vertical video compared to the same ad on the Home Timeline, while early adopters have seen -14% lower CPMs on average compared to ads in the Home Timeline.”

In theory, based on video consumption trends, this should offer more value. Previous insights from Twitter showed that tweets with video generate 10x more engagement than non video posts, while X claims that, on any given day, vertical video now accounts for more than 20% of total platform usage.

That feels like a lot, but if that’s correct, then there should be a level of opportunity in this new placement.

It’ll be interesting to see whether X actually does lean further into full-screen video, and make it a key focus of engagement, by opening to a video feed, or presenting it as an alternative UI option at some stage.

But based on these stats, its vertical video ad option could be worth testing.

X says that all U.S.-based advertisers will be able to launch vertical video ad campaigns from today.