What they have done is they're running a campaign of promoted tweets that contain videos, in their native interface. The video tweets get bumped to the top of the column on refresh so that every time you look at the interface one of them is running there. The thing is that if you stop the video and go away to another tab, then come back to the native Twitter interface's tab the video will be running again; in other words, these promoted videos default to 'running' and it doesn't matter how many times you stop the video and go away to a new tab, when you come back to the native Twitter tab the video will be running again. It's totally gag-worthy.
And it's inescapable. Social media is so hungry for revenue that they of course will compromise your enjoyment of their interfaces if it means earning a buck, and this pomoted video tweet is just another example of that phenomenon. It's not however quite as bad as when HootSuite locked a promoted tweet at the top of their feed; when they did that of course I, along with many other users no doubt, simply stopped using HootSuite and went to TweetDeck instead. While this new example of cashing in on people's attention is not as bad as that one, it's still not a pretty sight and augurs poorly for the future.
With Twitter's new ploy, you are constantly distracted every time you look at the native Twitter tab by the idiotic videos their advertisers have cobbled together just for this purpose. It's rigged and there's nothing you can do about it. However I reported one of the ads and Twitter got back to me within thirty minutes telling me they would contact me in future, but nothing has happened yet on that front. We'll see what happens and I'll keep you informed.