You’re missing the precursors:

Email -> Newsgroups -> CGI forums / IRC -> Slashdot… :)

The new Fediverse really is kicking up IRC and newsgroup vibes for this old timer. Its very exciting.

/r/AskHistorians - ruthlessly and efficiently moderated, but every single post a fascinating read. I should msg Zukhov to see if he wants to move ship to /c/AskHistorians.