To see a report on the collective user count for all realtime servers, select the Realtime User Count tab from the Reports page.
The Realtime User Count report includes a table and graph that show the number of Concurrent Hosts and Total Users on all realtime servers:
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Note: The Total Users count can be used to determine the number of users you are currently monitoring for License Statistics licensing. A "user" is defined as a unique username (a "user" could be a person or a machine) accessing the monitored applications. If one user accesses a monitored application from multiple hosts at one time, that user will count as two users.