Count meaningful participation over time
DAU means daily active users, WAU weekly active users, and MAU monthly active users. Each counts a user once within its period. A messaging app might count someone who reads or sends a message, but not someone whose phone merely receives a notification.
Stickiness compares a day’s DAU with that month’s MAU. If 20 people were active today and 100 this month, the ratio is 20%. It suggests how often people return, but does not mean every user was active on 20% of days.
Definitions make the metric
MAU figures from different products may not be comparable. Time zones, anonymous visitors, bots, duplicate accounts, and different definitions of “active” can all change the count. A high number can still hide unhelpful use, so teams also check retention and whether users get value.