There are a couple of angles, straight up representation of forum | subreddit threads after the conversation has moved on, "live" tracking comments as conversations progress, and moderation of live threads (including swatting | detecting trolls, spambots, griefers, etc) (oh, and retro sweeps looking for tail end spammers and their puppet networks eg: https://news.ycombinator.com/item?id=40800160 (with "ShowDead" on)).
In post analysis there's the whole ball of wax around decrufting chat threads to pull the meat best served to (various) AI, either for training, company | group intelligence, etc. Oh, and fingerprinting across multiple sources looking for common {group | individual} traits
The intrinsic issue with excluding all but those with a current PhD on chat would be the tossing of, say, those with dated PhD in theoretical physics or somesuch.
@dang obviously mods here and likely has a slew of lisp-y scripts | tools for giving various views, @jedberg was about for much of the early evolution of reddit and took part in a lot of discussions about presentation and implemented a few.
There'll also be useful input from any of those who've moderated | admin various largish forums | channels, etc over the years.