There was a mail client ( or was it the server itself? can't recall ) that did essentially what you are after. This was around a long time ago - pre www web. I

There was a mail client ( or was it the server itself? can't recall ) that did essentially what you are after. This was around a long time ago - pre www web. It would append a paragraph of pretty inflammatory keyword-heavy text at the end of each email. Stuff calculated to false positive any monitoring. Anyone remember/know what I am talking about?