Facebook call it a "new way for marketers to tell stories" - we call it video adverts.
When you start scrolling down your newsfeed you're going to have videos autoplay. Facebook says this is a "richer storytelling format".
Rather than having to click or tap on the content, videos will begin to play as they appear on screen — without sound — similar to how they behave when shared by friends now. If you don’t want to watch the video, you can simply scroll past it.
The social media giant surprised investors with record profits in October, as mobile revenues grew by more than 500 per cent in the third quarter of 2013.
Much of that is down to huge growth in mobile advertising. This step to increase advertising opportunities could do two ways - as users could be put off by irritating autoplaying.
Thankfully, the sound won't start unless the user clicks or taps that video in full screen. After the video finishes playing, another two will appear (in case you want to watch additional videos from the same marketer).