[tjic]

This has been done a dozen times before.

I worked at Authentica around 1999-2000. They got it working decently enough and were later bought by EMC. http://www.emc.com/domains/authentica/index.htm

The problem is that the data can be grabbed by image tools, etc., so you end up getting in a race to hack all sorts of libraries that can grab the screen, save text, etc.

[fec]

Great, this solution obviously addressing a burning need. May I ask, were previous solutions free and work on nearly all email clients?

I don't really see any major race happening. The best information grabbing tool already works great - people's eyes. The purpose of this tool is just to make forwarding a little harder, and add auditing and watermarking for environments where this added information can be acted on.