Every websites uses one form of algorithm or the other in order to complete certain tasks and meet some goals. Facebook, being the social giant that it is, was no exception to the list of companies that use their own specific Algorithm (Google is a good example of a company that does this), and named their algorithm as the EdgeRank Algorithm which was made to fit the purpose of displaying certain stories first within the News Feed of any user.
What the algorithm simply does is that it runs each and every story available in every person’s newsfeed through a specific filter which then determines which story is worth showing first on their newsfeed and which is considered boring based on three parameters:
The first is the affinity score, which basically compares two users in terms of how well are they connected with each other. This simply means that there is a higher chance of a story appearing in your newsfeed by a person with whom you frequently communicate with on the website in contrast to someone whom you rarely communicate with.
The second factor which determines the EdgeRank of a post is known as the Edge Weight. It simply means that every action that you make creates an Edge, and each edge has a certain weight to it, with some aspects having a higher weight than others. For example, a comment has a higher Edge weight than a like, which makes a story that you’ve commented on have more priority than something on which you’ve just given a like.
The third and final factor that the EdgeRank algorithm filters is known as Time decay which, as the name suggests, shows or hides a story depending on how old it has been. You would obviously want to be updated with new stories and data rather than something which happened 5 days ago, right?
The Wonderful World of Algorithms 