Disclosed is a method for dynamically applying a rights management policy
to a message by allowing an administrator to associate certain rights
management policies with certain senders and recipients of messages, with
groups of users possessing certain common criteria which define the users
and groups of users, with certain attributes of the message, and with
certain environmental attributes. Also disclosed is a method for allowing
an administrator to automatically update a rights management protected
message as it passes through a message transfer agent. The administrator
may determine either on a regular interval or an ad-hoc basis that the
message transfer agent scan the messages stored to determine whether or
not the content has expired. If the content has indeed expired the
administrator may take steps to have the expired content deleted
entirely, refreshed with more current content, or replaced with a
tombstone indicating that the original content has expired.