So ensuring that the Atrium org chart is up to date, and doesn't include departed reps, isn't missing new hires, and so forth is important for a well functioning Atrium instance.
When reps depart an organization (or move to a non-selling role in an organization), typically their selling behavioral activity stops. If they're not deactivated in Atrium, this lack of selling behavior (new opps owned, customer meetings, emails) can engender a number of problems - like a bunch of noisy warning alerts for that rep, negative impacts on "team average" data (messing up the average), and more.
An example of a departed rep that hasn't been removed from Atrium creating an erroneous warning alert and pulling down a team average.
Automatic Deactivation: In order to address this, when Atrium notices that a rep's Salesforce Account has been made inactive, Atrium will automatically deactivate the rep in Atrium, marking them "former" on the rep's admin page.
Atrium will further notify the rep's manager and the admins of the Atrium account with a helpful email, and transfers any folders or views owned by that rep to their manager.
Newly Hired Reps
Another way that an organization's Atrium org chart can get out of sync with reality is by not adding new hires to their relevant teams.
Tracking the ramp of a newly hired rep is a key Atrium use case, and if that rep isn't added to Atrium - a manager misses this opportunity, not to mention general performance visibility.
Automatic Activation: In this case, when Atrium notices that a new user has been added to Salesforce, it tries to figure out if that newly added user might be someone who should be added to the Atrium account.
Atrium does some clever business logic, leveraging the Salesforce role, title, and hierarchy data (as available - many organizations do not maintain Salesforce hierarchy - so Atrium's Org Chart Health system doesn't rely on this)