Facebook Edge rank is basically an algorithm used by Facebook to determine whether your posts should be ranked up or not in the news feed of your page as well as your follower’s page and what should be their position.
There are basically three measures by which this algorithm is been made which are as follows:
Affinity generally measures how engaging a Facebook post is basically it observes the relationship between the post creator and post viewers and prior to more strong and engaging relationship the more higher score is been given.
Different types of the post contain different range of weight it could be a photo, videos or plain text post. Weight depends upon how much that particular post got likes, comments, and shares. If there is a photo or video post posted but it didn’t get that much engaged then it will not be considered as a weighted post. However, if there is a plain text post in which there are likes, comments, and shares by mutual friends it will be posted up on the news feed as it is clearly more engaged in terms of figures of like, comments and shares.
A post which was posted few month ago automatically loses its space in the section news feed of people. However, if that post got comments and likes once it could be again seen in the news feed area of the connected users.
"hope you understood"