Facebook’s News Feed is sorted by an algorithm that many people call EdgeRank. It weighs not only the timeliness of posts, but their relevance to users. Facebook wants to make sure that the posts users see within News Feed are the ones they’ll be most likely to engage with. It’s why users tend to see posts from pages they’ve commented on and friends they’ve shared with more often than pages and people they don’t really post about. Mike Maghsoudi of PostRocket and Facebook expert Jon Loomer both explained the algorithm in posts recently.
Understanding Facebook’s Post-Sorting Algorithm