Facebook’s ranking algorithm introduced in 2010 was called EdgeRank.
EdgeRank was designed to decide which stories appeared in a user’s News Feed and in what order. Its name came from Facebook’s use of the term “edge” for an interaction or connection between users, pages, and content.
The original model is commonly described through three factors: affinity, weight, and time decay. Affinity represented the relationship between a user and the content creator; weight reflected the type of interaction; and time decay reduced the importance of older stories.
EdgeRank is often treated as if it were still Facebook’s complete modern algorithm. In reality, Facebook later introduced far more complex machine-learning systems and stopped using EdgeRank as the name for the full ranking process. The term remains useful for understanding the News Feed’s early history.