Traffic
Daily active users
Also called DAU.
Daily active users is the number of distinct visitor identifiers that sent at least one hit on a calendar day. It is the base number for stickiness, which divides it by a longer window.
How it is measured
Count distinct identifiers per day in one fixed time zone and ignore repeats. A person who loads fifteen pages is one. Most tools reset at midnight in the property's time zone, so a reader who visits at 23:50 and 00:10 counts in two days.
Tarsier keeps nothing across days by design, so a daily count of visitors is the cleanest unit it offers. It can tell you how many came on Tuesday; it cannot tell you which of them also came on Monday.
Worked example
A paid newsletter site has 3,800 subscribers and sees about 1,150 distinct visitors each weekday. On Saturday the figure falls to 410. Nothing is wrong. The newsletter goes out on Tuesday mornings and people read it at their desks.
The editor wants a Saturday edition and compares 410 to 1,150 to estimate demand. The better comparison is last Saturday to this Saturday.
How it differs
Daily active users looks at one day. Weekly active users pools seven days and will be lower than seven times the daily figure because the same people come back. Monthly active users pools longer still. The gap between them is what stickiness describes.
Common errors
Quoting the best day as typical. Ignoring weekday shape. Mixing time zones across tools. Treating the figure as customers when it is visitors. Counting internal staff and uptime probes as users.
In practice
Chart the daily figure for four weeks and read it by weekday. Take the median weekday, not the maximum, as your baseline. Remove known internal traffic first and note the time zone beside the chart.