A supplementary electronic address assigned to a user or group within a directory service allows messages sent to it to be automatically routed to one or more designated primary mailboxes. For example, mail directed to `salesgroup@example.com` might be configured to forward copies to the individual inboxes of all members within the sales department.
This functionality offers several advantages, including simplified communication by providing a single, memorable address for multiple recipients. It also facilitates organizational changes, as the underlying recipient list can be modified without requiring external parties to update their contact information. Historically, this mechanism has been a fundamental element in managing distribution lists and streamlining internal and external communication workflows.