> Where is the public open chats of cyber space?
It used to be every tech-savvy person had their own PhpBB instance and built small communities with that. All that has largely migrated to Discord, Reddit, Facebook Groups, and to a lesser extent: Lemmy & Mastodon. There's also quite niche and bespoke communities like Subreply[0], Tildes[1], and Raddle[2] (Built with Postmill). I prefer the Reddit style Karma system over the 'Micro-blogging' system. Everyone has their preferences.