So I've created a Discord server for one of my forum groups. What is permitted and not permitted when trying to invite people to a Discord server?

I'm not sure if staff have ever addressed it directly, but I have seen many people post them before in their private forum groups without issue. I mean, Keith has even invited us his temporary Subeta one in a site banner so I don't see why sharing links in your group would cause any issues. Posting something like, "here is our forum group server (link)" is fairly commonplace nowadays.

However, moving offsite means staff likely can't help you if you're having problems with other users so moderating becomes up to the server owner(s). I recommend using common courtesy when interacting with other users offsite.

So people have posted an invite link in a forum group thread without issues?

I've seen people send IDs through comments so I know that's a thing.

Yeah, usually forum group owners have a dedicated thread with a permanent invite so they can ping people to it and those people can then join on their own. I wouldn't go around recruiting people without their consent first though. But if someone says "yes, I would like an invite," I don't see why you couldn't offer them one.

I agree with though, filing a ticket to get the exact do's and don'ts from staff is a good idea because this is kind of a grey area. What is commonplace and what is actually allowed can be two different things sometimes.