What is Engagement?
Engagement is the set of actions a person takes with the content beyond seeing it: liking, commenting, sharing, saving, clicking the link or the profile. Each action carries a different weight for the algorithm. Saves and shares are worth more than likes, because they show the content was useful or worth passing on. A comment is the most valuable when it starts a conversation, and it is also what opens the door to an automatic reply in the DMs.