Discourse
A mature open-source community platform with topics, tags, trust levels, moderation, direct messages, badges, single sign-on, plugins, and mailing-list-style participation.
Why use it
Unlike relying only on transient chat, teams can preserve guides, mods, bug discussions, and announcements as searchable knowledge while permissions and moderation develop core contributors.
Where it fits
Use analytics, feedback, player support, and updates to fix issues and decide what to improve after launch.
What to check
The GPL software is free to self-host but deployment, email delivery, upgrades, spam defense, and governance require real effort, while official hosting is plan-priced; a forum also does not replace fast live chat.