That is interesting. I think they're finding out the profits they make increase as user retention is increased.
I think people are getting bored with spam content based on their likes and using less of Facebook. I think this shift will be more like what youtube already does as far as keeping people on their site as long as possible to see more ads on a per day basis.
How is this happening? Sorry, but not much YouTube for me these days, what did they change?
The entire algorithm of youtube is set-up to constantly figure out what you view and try and introduce you to new similar content by suggesting similar videos. I'm not 100% sure how it works, but from watching people that make a living off youtube, youtube tracks all your actions on youtube to try and keep you on the site. The longer you're on the site the more ads that you watch.