Fore More Distinct ID Info
This article only discusses how unique users are counted in the main reports. More help articles can be found in the greater User and Identity Management section.
Mixpanel's unique identifier is called distinct_id.
Mixpanel can keep track of actions in your application right down to the individual customer level. This is done using a property called distinct_id. The property can (and in most cases should) be included with every event you send to Mixpanel to tie it to a user. Distinct_id plays a vital role across most Mixpanel reporting. Here's how:
Segmentation and Formulas
In the Segmentation and Formulas reports, distinct_id is used to determine uniqueness. When you filter a report down to look at only uniques, Mixpanel is showing you the count of unique distinct_id values that sent that event. When you view averages, it is showing you the average number of events sent per distinct_id per hour/day/week/month.
In the Funnels report, distinct_id is used to follow a given customer through a funnel. When the report is calculated, we take the count of unique distinct_id values that sent the first event. We then follow that pool of ids through the subsequent events, calculating the drop off as we go.
In the Retention report, distinct_id is used to follow a cohort of users through time. When you select a value under "show me users who did X," we collect the entire pool of unique distint_id values that send that event on the given day/week/month. We then follow that group of distinct_ids forward in time to see if there are any the events you specified in the following day/week/month long buckets that were sent with that id. If so, we include that id when calculating the percentage that we display for that cell in the chart.
Distinct_id plays a dual role in People analytics. Firstly, it is the unique identifier for that part of the tool. Data sent to the people section of Mixpanel is dispatched to a distinct_id. If the id already has a People record tied to it, then the call modifies or updates the existing entry. If the id does not already exist, a new entry is created for that id. The distinct_id associated with a People analytics entry can be seen by inspecting the URL when in the profile view (click a user in the explore report).