This metric is capturing the number of users who opened the app at least once in the last 24 hours. This means that a user who opened the app once and a user opened the app 10 times, over the last 24 hours, are both only counted as one Daily Active User. Any time that you are looking at DAU over an aggregated period of time (i.e. a week, month, quarter, year, etc) you are looking at the Average DAU. So for instance if you are looking at Netflix’s DAU for April 2018, then you are looking at the average of the 30 daily DAU values from April.