Probably Information Rights Management in Outlook (Office): http://office.microsoft.com/en-us/help/HA101029181033.aspx http://office.microsoft.com/en-us/help/H

Probably Information Rights Management in Outlook (Office): http://office.microsoft.com/en-us/help/HA101029181033.aspx http://office.microsoft.com/en-us/help/HA101029181033.aspx I have no inside knowledge, though, but I doubt they built their own system. And you can still take a screenshot with a third-party program, and myriad of other ways to get around it. If you read it on the screen, you can forward it -- just takes a little more work.