What is the difference between Departments, Disciplines, and Communities?

A Discipline groups a set of Departments. As such, departments are more specific than disciplines. For example, a discipline at a hotel may be named Room Operations and departments within that discipline are Front Desk, Housekeeping, and Concierge.  

Communities determine the visibility of tasks. Task are assigned to a community. Users are granted access to one or more communities. If the task is assigned to a community that the user has access to view, then that task will appear in the Tasks page for that individual. Tasks assigned to a community which a user does not have access to view will not appear on the Tasks page for the individual. Community also limits the data that is presented on the Dashboard, Company Summary, and Reports pages. This is a common reason why one person’s Dashboard or Tasks page may look different from another person.