Facebook changes how the News Feed behaves from time to time where they change the underlying algorithms that affect ranking of various elements in the feed.
One way people use Facebook is catching up to news stories on the Feed which are shown to you based on your interests. We now read articles that are shared by the publisher via link (which opens the publisher’s website) or those that are shared as Instant Articles which load way faster than the former.
Instantaneous loading articles have an obvious advantage due to the fact that you don’t have to wait as long to read an article compared to the generic way of waiting for the webpage to load. Apparently according to Facebook, as many as 40% of website visitors abandon a site after three seconds of delay. they have received feedback that it is frustrating to click on a link that leads to a slow loading website.
This is why they have decided to make an update to the News Feed to be effected in the coming months that will show people more stories that load quickly on mobile. Those that load slower will be shown less in your News Feed.
Facebook will be considering the estimated load time of a webpage when someone clicks it, user’s network connection and the general speed of the corresponding webpage. If all these signals indicate that the webpage will load quickly, the link to the webpage might appear higher on your feed.
This change will of course affect Pages where they said that slow webpages will see a decrease in referral traffic but they anticipate that most Pages won’t see any significant changes to their distribution.