On Facebook, “monthly active users” (MAU) refers to the number of unique registered and logged-in users who have visited the Facebook website or app within the past 30 days. It’s a key metric used to measure the platform’s overall user engagement and reach. Key aspects of MAU on Facebook are (a) Only unique users are counted, meaning a user is only counted once, regardless of how many times they visit or use Facebook during the month. (b) A user is considered active if they log in, use the mobile app, or visit the website, even if they don’t perform any specific actions like posting or commenting. (c) MAU refers to the number of users who were active within the last 30 days. (d) MAU is a valuable metric for understanding the overall size of Facebook’s user base and assessing the platform’s growth and popularity.