Way back in the heyday of forums people on forums I'd frequent would create their own and tell us about them. Sometimes they took off but mostly they didn't.

In response to one of these I created a lengthy post with bits of advice derived from my observations about what worked along with a bit of guesswork. Annoyingly there's no reasonable way to find that post - it'll probably have been on the EU PSP forums and those are long gone. There's probably some record on Archive.org but realistically it's not worth the trouble.

Perhaps a bit of context is appropriate at this juncture. Forums as a medium are, for the most part, dead. There's a few kicking about but I know my favourite one, YakTribe, updated its forum software and the user experience is now truly horrendous. I'm trying to get over it to continue to contribute but it's like the site actually wants me to leave.

Something that doesn't fulfil the same role but is inexplicably popular is Discord. It seems that any given community has multiple Discord servers. The system works reasonably well and it's certainly a step up from IRC, but its linear nature doesn't lend itself to ongoing discussions. In an attempt to support this admins create countless channels. For bigger servers this is workable, although any time a discussion veers into a different area there's always someone saying "best take this over to #specificChannel". Usually when that happens I just give up. It kills the flow. If there was a WhatsApp-style quote system then the channel switch could be handled somewhat organically but at the time of writing nothing like that exists.

Now, here's where that old forum advice thing comes in. When Dave decides he wants to setup a Discord server for his thing he imagines that he'll hundreds of users. They'll want to spend lots of time there talking about countless subjects. Better get the work done now and create specific channels for each subject!

People starting their own forums would do exactly the same thing. They'd create loads of subforums. Do you know who mostly starts lots of topics in a silent forum? Extroverts and idiots. The former are like gold dust and the latter aren't good at stimulating discussion.

The end result is 1 - 5 topics in each forum and a constant feeling of emptiness. That doesn't foster a community spirit and as a result they'd usually die on their arses.

Anyone wondering about approaches I know to work:
Create 2 - 4 sections. One off topic and the others related to broad areas of the subject materials.

If a subject comes up multiple times then it's time to start thinking about creating a new area for that - otherwise the existing area will become the de facto right place for that, often at the expense of other discussions.

The other thing to bear in mind is which tool is right for the prospective audience.

I'm not a fan of Facebook. I never have been. I was a late adopter and I don't use it to share many of the traditional things. In fact I mostly use it for hobby communities and work. Like the medium or not there has never been a more active Gorkamorka community anywhere. At the time of writing there are more than 2300 members and it's rare for a day to go by without someone posting something.

Multiple forums have existed over the years, there's several Discord servers with Gorkamorka channels, there's a subreddit, and probably other things too. None of them see more than a few words exchanged per month. Some don't see that per year.

A fresh-faced young nerd of 17 asked me:

"have you ever considered making a gorkamorka specific discord?" 
...the other day and that's what got me started on this train of thought. At the time I asked him what that would accomplish and he didn't have an answer for me. I wasn't trying to be harsh, I was basing it on the fact that I run the Gorkamorka channel on the /r/Warhammer Discord server. There are over 3000 members on there. I've probably had less than ten proper conversations about Gorkamorka on there ever. I'm also on an Ork-specific Discord server. Fewer than five Gorkamorka conversations in its channel.

Each time one creates a new space for a subject there's some filtering. Uptake isn't perfect. Any time there's an opportunity for something to be a bit too much faff then a certain percentage of users will vanish.

As a result the hypothetical best tool for the job might be much better but unless the existing userbase is crying out for a move then it's rarely worth it. Even if it is then care must be taken in rolling out the new setup so as to encourage a bit of esprit de corps.

Incidentally my favourite use of Discord has been for programming assistance related to my Twine projects. It's a medium that works well for that sort of thing as its features are richer than IRC and the persistence of conversation means one doesn't need a client running the whole time to get some context.