I don't even understand why do email clients have to use a dedicated protocol (let alone SMTP) for email sending. If I were developing an email client and didn't care about established conventions, I would just make it put outgoing email to a dedicated folder via IMAP and let the server pick it there and go on sending it to recipients servers over SMTP.
While email is an <i>application</i> that is, for example, tightly tied to DNS (check the SOA record), SMTP is a <i>protocol</i> that has got a lot of improvements, addenda, enhacements and the likes.
But, IMHO, it is far from being comparable in features and security with other (modern) communication protocols like XMPP.
Funny i just created an expect tcl script to do SMTP sends. I’ll add these folks to my relay list!<p>I discovered how much i like expect/tcl. There’s no need to use a library. A simple 100 line script does what i need.
Why do we even use SMTP and IMAP when we could be using XMPP instead?<p>I know there are some caveats preventing XMPP from becoming the one protocol to rule all the chats, but why not use it for email exchange?