...
The list of users that are currently logged into Salesforce during any period that usage is tracked (active user sessions)
The total users count, i.e. the list of all users who have their active Salesforce accounts and can log into Salesforce. The total users count corresponds to the number of all licenses purchased by a company
Note: Due to its experimental status, monitoring Salesforce licenses is disabled by default. If you are interested in the feature, please contact X-Formation Support to obtain a simple instruction on how to enable monitoring of Salesforce licenses.
...