I had a brief conversation with Dan Mosedale, of the Mozilla Messaging crew, where I stated my stance that such a replacement is non-pragmatic. He suggested something interesting: most mail access today is not via IMAP, but via the web.

That is a perspective I hadn’t considered, but it is certainly true. Most people receive email through Microsoft, Yahoo, Google, or AOL. Through the use of Ajax techniques, much of this mail is being delivered over HTTP. It is by no means a stretch to imagine IMAP being replaced by an HTTP-based protocol, given an effort to standardize the data format transmitted in the requests and responses.