US Patent 7305430 Reducing data storage requirements on mail servers

A single copy of an incoming message addressed to multiple recipients is stored as a shared message on a server and the message's size is determined. A recipient count indicates how many of the recipients of the message have mailboxes on the server. A total amount of storage that would be needed to store copies of the message in each of the recipient's mailboxes is calculated from the size of the message and the recipient count. The calculated total amount of storage is compared to a predetermined limit. A selection is made between storing multiple copies and storing only the single copy of the incoming message on the mail server responsive to the comparing.