Formula
Count of distinct users with a qualifying event in the trailing 30 days
How to measure
Count distinct user IDs with at least one qualifying event within a rolling or calendar month.
Why track it
MAU is the standard scale metric reported externally, though it should be paired with DAU/WAU to avoid masking declining engagement depth.
Example
A social app reports 12 million MAU this quarter, up from 10 million the previous quarter.