I have seen a couple of cases of people (or machines) saying "Send an email to <address> with <some word> in the subject line." That seems easy for a human to

I have seen a couple of cases of people (or machines) saying "Send an email to <address> with <some word> in the subject line." That seems easy for a human to carry out and for a machine to recognize. This seems to address your objection: In this perfect world this supposedly is done by the sender... but that, too, is fraught with problems, because that takes a certain level of skill on the sender side and now you've lost the aspect of email where you just click "New Email", bash on the keyboard for a bit, and hit "Send" It is indeed possible to define little machine interfaces like this and for users to learn and use them. A more complicated interface would of course be more difficult; maybe you would only try to ask technical users to do that, and have a machine send back "Did not parse correctly" if it did not parse correctly. If it becomes common and useful enough, perhaps you could make email applications that provided buttons or whatever to machine-generate machine-readable instructions, and big-business clients could instruct their employees that deal with your machine to use such an application. And maybe you could bug Gmail developers into implementing it as an optional feature, disabled by default--maybe in that "Gmail Labs" thing, although this has a different source. If that doesn't work, then maybe you could duplicate all of Gmail's nice functionality so that those employees feel fine using your email application. Eventually you might get something that could be called a standard out of this, but you would start with just a small use case. It does seem likely that expecting an interface to work with no prior exchange of instructions ("put word in subject") between the receiver and the sender is, well, hubris. But I suspect you can get a fair amount done with tiny interfaces that are easy to learn. See also: http://unqualified-reservations.blogspot.com/2009/07/wolfram-alpha-and-hubristic-user.html http://unqualified-reservations.blogspot.com/2009/07/wolfram...