I've always wondered about the viability of an email client that behaves like a chat client. Instant send with the enter key, messages in bubbles, etc. You get all the fun of IM without additional infrastructure or services, and in a standard way too. No walled gardens of different apps.
Could be a pretty cool UI solution to have a chat client that uses PGP encrypted e-mail in the background, but Gmail SMTP has a send limit of 100 e-mails per day. You would run into that rather quickly with a chat UI.
I guess the chat client could do all the e-mail sending from some of their maintainer e-mail servers and not from under the chat participant e-mail. Then we would start losing comaptibility with other e-mail clients though. Although not completely, as we could set Reply-To headers and when another e-mail client replies to user1234@chat-client.com, we could just forward it to the correct e-mail.
Kind of. Imagine more like Google Groups or HN but with notifications when someone replied.
I guess if you use mailing lists for topics you can subscribe to, and cc'ing people for @mentions inviting them to reply, then yeah! Email can do it all. So why is email considered such a time sink? Because people don't filter conversations coming from the outside. But if they just set up a filter, then literally email is a Slack killer, no?