WSJ reports today on Authentica which offers programs to secure e-mail and net documents against unauthorized access or usage by setting parameters for who can see the mail or documents but not copy, print or forward them. Email and documents can be set to expire or erase themselves at any time. The programs plant commands in the docs which lie in wait on someone else's box ready to do what the originator wants with creative property. The programs are being offered for free to help promote the product: http://www.authentica.com It is export controlled, so the license says, and you will have to swear to abide BXA regulations. It would be interesting to see how to transgress this allegedly highly secure digital content protection.
