A mailuser combines some of the attributes of a full mailbox user along with the characteristics of a contact. Mailusers provide a useful “half-way house” that enables administrators to provide logon facilities to Office365 while continuing to provide an external email address.Organizations that use associates often use mailuseraccounts to provide logon facilities to these personnel while forwarding their emails to their externalemailaddress. The mailuseraccounts can be assigned to a manager and department for administrative purposes.