In the article linked below, it's an example from the NHL playoffs. But it could be anything. Facebook announced it has 4 billion video views a day (although a video view is counted when it plays for 3 seconds, and with autoplay in newsfeeds, that has to boost numbers). But the massive reach Facebook has is only one side of the story - in monthly active users (MAU), YouTube is not far behind Facebook. But to discover content on YouTube, you need to a) be a subscriber to a channel and get (sooo 90's) an email with links to a new upload, b) search for a video or c) see it being shared on social media - mostly Facebook. With c) declining, Facebook has a superior distribution approach because of the newsfeed algorithm which will make it possible to distribute a video to an audience that didn't ask for it or actively tried to find it. And in most cases, this will make the majority of views.
It's only a matter of time until most companies optimize their videos for Facebook instead of YouTube. Just like many publishers already optimize their stories for Facebook instead of search. Interesting example is PopSugar's approach described here: