The People window is used to maintain data about users. This includes their email as well as their login credentials. Once the data is entered users can be drag and dropped onto a machine.

People either own the machine or they are assigned to it. It depends on the organization or lack thereof. In either case a user has login credentials for the machine as well as email credentials, often more than one email. In the People window you maintain user data such as login long name, short name, and password as well as whether the user has admin privileges In the Email tab you enter the login credentials for one or more email addresses. You can also enter mail server information.