...compared to other communicatons channels, I rather like forums, but yes, this forum is next to abandoned, and forums are (relatively) high-maintenance because somebody has to keep the software up-to-date and keep an eye on how successful spambots are at registering...
...so of course I wonder if it's a significant maintenance work load. And, with no new development going on, does the software require patching often?
I wish I could offer advise, but I really can't. But I can tell a story:
Local anarchists where I operate, used to have a forum. It got created in 2006 when most of the crew was fresh out of high school. Data security practises were typical for the day and age, so most likely, it was a gold mine for cops (if they ever bothered, because my colleagues were light on illegality and heavy on other organizing). It got popular too, attracting as many as 500 simultaneous (human, not bot) visitors in the beginning. Then it dwindled down to a stable 20 or so. Of course we had trolls and at some point, the forum was really high-maintenance in terms of remaining open to everyone without getting overrun. Quite a lot of useful information got exchanged and... at some point about 5 years later, a generation effect seemed to hit it. You see, my colleagues have a fairly high political drop-out rate, either becoming all busy with raising a family, becoming entirely dormant or going off sideways either to hobbies (e.g. street art) or single issue politics (e.g. ecological topics) or downgrading from activism to community organizing. At the sharp part of the drop-out curve, people gradually moved to social networks (!) and talk eventally winded down. Those who needed real security also moved elsewhere (e.g. squatters: to e-mail and instant messaging).
As for that forum, it still exists, in case it might need to be activated on some occasion to draw more attention. But nobody in their right mind, and probably nobody among our crew, would ever dream of usin it for underground stuff again. For above-ground activism, maybe, on some peculiar day, it might even get restarted.
As of currently, that forum is getting about 3 spambot registrations per month, unless the admin has entirely closed registration. At some period, it also got hacked and restored from backups about once per two years. :P Partly due to admins being too busy (I was not among them) and partly because the really cheap hosting provider (!) had a habit of getting compromised.
So the only forums which are active and which I frequently visit, seem to be a model aviation and RC forum and a tech support forum these days. Used to be about 10, now down to 2.
As for me and this forum, I wish I had time, but I have created for myself so many projects and chores that I rarely do. So I stop to visit very rarely and very irregularly. Of course I would miss it, but I already do. And to be honest, losing access to this place would not unsettle my routines.