this is an interesting question i've had banging around in my mind since well before Reddit's implosion (and Discord's enshittification), but which seems really worth asking now.

you can't blame Reddit and Discord or their imitators entirely for these going out of style, but they've sure put the dagger in a lot of remaining ones, and i kind of wonder if they're just in an irreversible and terminal decline a la USENET. i can only name two or three i even consider checking anymore, and i'm not sure how sustainable any of those are long-term.