Some weeks ago, I’ve come across Delta Chat, whose main thing is “(near) instant messaging using your email”
That left me thinking, has this been attempted before? If not, why? Also, why (besides servers’ limitations as means to fight spam) isn’t this solution used more often, given that e-mail has been a decentralized solution for well over 40 years now?
Besides the other reasons here the biggest reason IM took off is the “I” part of the name. Email measures its SLAs in days. A lot of the retry intervals are set 4 hours with timeouts of 72 hours. It wasn’t designed to be “Instant”. Granted probably 90%+ of email gets delivered in under 5 minutes, but imagine having a chat and your responses are delayed 4 hours. Just send an email at that point.
I once tried to explain instant messaging to an older woman but she didn’t get the difference to email because she’d regularly use them to instantly chat with her son. That was two or three decades ago. While in theory emails can take days to be delivered the reality is that for a human it is “instant”.
not only that, but intermittendly delayed. Very possible that it will be instantanously 99% of the time, but randomly a message will be delayed by hours and you will probably not even know it
Plus there’s the issue of overhead. An email might be simple, but look at the raw message and there’s a lot of stuff being sent for each email.
So this is true (and increasingly so recently), but a lot of that overhead is technically unnecessary for the message to be sent and received; a lot of it is information about transmission and DKIM validation, spam protection, sender verification, etc; and then a TON of it is HTML for display. For a known receiver to send a message to a known recipient, I believe that a text-only email that’s cryptographically signed for identity validation could potentially be a tiny fraction of the size of a big huge HTML email.