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?
My email provider kept blocking my DeltaChat-created messages, and indeed locking me out of my account for them. Presumably because the encrypted gobbledygook looks likes spam. The open nature of email really is its Achilles heel, unfortunately.