Facebook have announced that they have added the time spent viewing a Facebook post to their algorithm for post ranking
We are adding another factor to News Feed ranking so that we will now predict how long you spend looking at an article in the Facebook mobile browser or an Instant Article after you have clicked through from News Feed.
Source: https://newsroom.fb.com/news/2016/04/news-feed-fyi-more-articles-you-want-to-spend-time-viewing/
Likes, clicks and comments are still important but now longer articles might start appearing higher in the news feed.
But before you just start putting up long Facebook posts they will be putting in a time threshold so there will not be the “Longest post first” scenario.
We will also be looking at the time spent within a threshold so as not to accidentally treat longer articles preferentially.
This change will be rolling out over the next few weeks so have a think about how you publish your articles. If you are using an auto poster from your WordPress blog have a look how much information can go with it.