I'm personally of the opinion that 418 shouldn't be considered a joke response, but would actually useful as 418 "Unsupported Device". What response should a p

I'm personally of the opinion that 418 shouldn't be considered a joke response, but would actually useful as 418 "Unsupported Device". What response should a printer give if you asked it to send a fax, but you have a base-model printer that doesn't support sending faxes. From the perspective of the printer, I know what you want (i.e. not a 404) and you've asked for it correctly (i.e. not 400 or 401 or 403), but I can't do it, and this does not indicate an error on my part (not a 500 or 503). Thus, 418: Unsupported Device. Perhaps this too much of an overlap with 404 (I don't have that resource) and 501 (I can't do that verb to that resource), which I assume is why there's not a huge need for it. But if we're going to have 418 exist and receive browser support anyway, it might as well have a useful meaning rather than just exist as a joke. This interpretation is fully in keeping with the non-joke meaning of the original RFC, as a teapot is a device that does not support brewing coffee.