I greatly miss Usenet newsgroups -- NNTP ones, not yahoo or google groups, or any of the pale http immitations. The best were usually moderated of course, but even unmoderated ones often had high signal to noise. I imagine how they might be now with rich text rendering, e.g. embedded TeX and images.

Good newsreaders (MT-Newswatcher on MacOS springs to mind, but also fast console programs like tin) really helped. There were no 'likes' or 'vote' buttons. But there was the ability to whitelist or blacklist certain authors by adding them to a user's 'killfile', leading to the wonderfully pithy permanent downvote reply: