excerpt from an Interview with the Thing (http://epidemic.ws/downJones_press/THE_THING_Interview.htm):
Q: Your latest project, downJones [sendMail], is a demo of a virus for webmail sofware that slips short phrases into the body of any e-mail. In other words, if my provider installed this program, people I know could receive a message from me that I only partially wrote. As far as we know, this is quite an innovative concept for an e-mail virus, whose aim usually is to infect files on the user's hard disk and not to change the meaning of the messages sent or received. What inspired you to write such a virus, precisely how does it work, and what are the possible uses?
A: When our - Softwares of Trust - are able to "open" and read documents correctly during daily use, we tend to automatically believe that all our data is intact, and to question its integrity would seem like madness. Most users are inclined to think that a file is corrupted only when it is unreadable. This is not enough. downJones [sendMail] is an elementary experiment with the possible corruption of the meaning inside data. It is an example of a language virus. It is made out of two simple functions: the first one reads the text, trying to recognize the language. The second one tries to insert within the discourse a phrase that is picked up randomly from a list of sentences -- in a syntactically credible manner, of course. Applied to a web-mailer software, our downJones [sendMail] demo is transparent--it reveals the trick--but the possibilities for its use are multiple and the effects of such a "virused" communication are quite unpredictable. It is difficult to verify that what I send you is what you receive--and the diffusion of the "digital signature" is still to come. downJones [sendMail] is an "open case," both on a technical side and on an interpretative one. It would be interesting to try it for a month on Yahoo and for a few years on Microsoft Office. But that is probably illegal.