There are also technologies new-ish to this kind of site included like every thread is a live thread via websockets, your post and comment scores update in realtime, notifications are realtime, you can DM other users and receive your messages immediately. So it's distinct from the everything is a hard page load world of 10 years ago and blurring into native software in a browser.
What I'm working on right now is a SwiftUI iOS app, because one of the most interesting observations from analytics has been that the internet is 70-80% mobile devices now, contrary to my 10 years out-of-date conception that people were mostly using the internet on desktops. So a mobile app seems non-negotiable to reach most users. I have a PWA already, but early users have repeatedly requested an official App/Play Store presence.
The stack is somewhat unique in that it's built with a Swift/Vapor framework (https://vapor.codes/) backend, with a more standard React Router 7 (SSR) frontend. I picked this framework mostly because I'm historically an iOS dev, but have found it to be very capable in its own right. I later discovered Apple themselves are using Vapor for some web services and have a team devoted to maintaining the server library (SwiftNIO https://github.com/apple/swift-nio) the framework is based on.
Anyway, it's very early still with launch via Reddit itself only 3 months ago. One of the biggest issues is getting it in front of people without appearing spammy and cold-start on a social platform is also brutal, you need users to get users, and round and round it goes. I may do a Show HN in the future if there's any interest in a real experience using Vapor as a production backend.