You can build privileged services that can log onto multiple mailboxes by using Microsoft Exchange Server functions. These functions enable you to build a range of services that might include the following two examples:
Voice mail application that allows users to call into Microsoft Exchange Server and retrieve their messages over the telephone. A user might enter a personal ID code and an access code on their touch-tone phone, whereby the voice mail application reads the user's mail over the phone by converting the message's text to analog voice signals. Entering other codes would result in messages being saved, deleted, forwarded, and so forth.
A utility that performs operations on mailboxes, such as moving them from one server to another or backing up an entire mailbox on a different server. Without the mailbox logon functions, Microsoft Exchange Server will not permit these actions because it does not allow multiple mailboxes on different servers for a single user.