Perhaps they went to Facebook?
I remember how exciting it was when I stumbled on forum-based websites, probably around the turn of the millennium. I found I could 'speak' to folk, in my own country as well as from others, about subjects I have deep interest in.
Discussions ranged far and wide and were interesting and stimulating. Mine were mostly about serious topics although we regulars would still have a laugh too at times. But I didn't and still don't use social, chatty forums.
One thing that has definitely changed for all us regulars from those early times is we're twenty years older. Even if we are still writing about the same subjects the chances are that we'll have 'done' them almost to death. And even the former fun-makers, game-players, jokers and what have you may have grown bored and just moved on.....
In my own speciality very little appears that I didn't already know about, that I haven't discussed. I still try to help earnest seekers although I won't give much time and effort to casual enquirers.
The dozen or more websites where I was once a regular contributor have either closed or are moribund. That may be because of lack of interest in the subjects or an unpreparedness to spend time writing properly - 'text-speak' is so much simpler and undemanding.
Alternatively it may be that folk search online and think what they find is authentic - which it might be but the web is awash with folks' ideas and beliefs.
Sorting the wheat from the chaff is no easy task at times.