People seem very focused on technological solutions to online communication (ActivityPub, Indieweb, this absurd BlueSky idea), but the hyperconversation approach is trying to prove that the problem is a human problem. If you read and listen to each other and try to respond thoughtfully and carefully - and try to find your own style and wee innovations along the way - you start to feel like you don’t need anything more complicated than a TiddlyWiki!
That's Kicks Condor writing about wiki-based communications. I've participated in a few short exchanges via my wiki. It's fun. It's also cumbersome and kind of awkward but that's sort of what makes it great. On my wiki I call them "Letters" but "Hyperchats" has a cooler ring to it.