[there]

Sooner or later I think a RESTful HTTP or SPDY API will replace IMAP, and (for client-server comms at least) SMTP.

"replace" is a strong word. IMAP (version 4 that most things use these days) has not replaced POP3, but is a much-improved alternative that is well supported on the server-side and client-side. the reason it was able to gain such popularity was that the spec (RFC 2060) came out in 1996. how many different POP3 clients were even around back then? (according to wikipedia, outlook express 1.0 came out in 1996.) a lot of people at that time were probably still reading mbox files in pine through a telnet session or never e-mailed anyone outside of AOL.

The problem with email for most of its life was that there was little competition.

and now e-mail is so prevalent that making changes to the core protocols like SMTP, POP3, and IMAP is nearly impossible. we've been living with SMTP since 1982.

every provider that supports IMAP still has to support POP3: google, yahoo, AOL, MSN, and probably every university and ISP. SPDY will never completely replace HTTP, so sites using it will always have to run both servers in parallel, just like IPv6 will have to run alongside IPv4 for many years to come.

for a new protocol to replace SMTP or even augment it, it would have to be designed, refined, turned into an RFC, then probably debated some more, and then support would have to be added to all of the major MTAs like sendmail, postfix, qmail, and exchange, along with many firewalls, spam filters, and other in-between devices. clients need to support it, so that's outlook express, thunderbird, iphone, android, blackberry, and every other little device and program that speaks it. getting the manufacturers or maintainers to implement support for new things is hard enough, but actually getting all of their customers to switch or upgrade is an even bigger problem (see IE6, DNSSEC, etc.).

maybe it's the rate of change in things like HTML and CSS over the past few years that gives the false impression of being so easy to do.

[zokier]

> a lot of people at that time were probably still reading mbox files in pine through a telnet session

I'm still reading (some of) my mail in pine through a ssh session.

[rvkennedy]

"replace" is a strong word

exactly the word I intended to use: but "sooner or later" can be a long time coming. I know POP still exists, hell, gopher still exists but I'd say it's been replaced in all practical terms.

every provider that supports IMAP still has to support POP3

In what sense - do you mean practically, or in some technical way?

for a new protocol to replace SMTP or even augment it, it would have to be designed, refined...

Right, but I restricted this to client-server. Any protocol you like can replace SMTP for client-server, simply by taking messages from the client, then sending them on via SMTP. This is how Courier provides mail sending via IMAP connections.

maybe it's the rate of change in things like HTML and CSS over the past few years that gives the false impression of being so easy to do.

It's not easy, and it won't be quick. But I like many slow, difficult things, I expect it to happen at some point. In fact there's already a draft RFC to for RESTful HTTP mail retrieval: http://tools.ietf.org/html/draft-dusseault-httpmail-00

[rvkennedy]

Wow, someone really doesn't like draft RFCs!