Why do online communities and forums die?
Through a set of failure modes that recur so reliably they are close to a lifecycle — and most deaths are social rather than technical, which is why migrating to better software rarely saves one.
The recurring causes:
Founder and moderator burnout. Communities are held together by a small number of people doing unpaid, invisible, frequently unpleasant work. When they stop, nothing replaces them, and the decline is usually visible within months.
Growth destroying the thing that attracted people. A forum works at a size where members recognise each other. Past that, norms stop being learnt by observation, the same questions recur endlessly, and regulars leave — the "eternal September" pattern.
Tone drift. A community's culture is set by who it tolerates. Failing to remove a persistently hostile member drives out ten polite ones, and the loss is invisible because people leave quietly rather than complaining.
Unaddressed conflict, particularly between moderators, which splits communities.
Platform decisions — an API closing, pricing changes, a policy shift or an acquisition — which have killed many communities outright.
Discovery drying up, as search traffic and inbound links decline, so no new members arrive to replace natural attrition.
Migration to closed spaces. Conversations move to group chats and private servers, which is better for the participants and removes the public archive — a real loss, since the answers are no longer findable.
Commercialisation, where a community is monetised in ways members experience as extraction.
What keeps communities alive: a succession plan and more than one moderator; clear, enforced norms applied to popular members as well as unpopular ones; a reason to return that is not only asking questions; deliberate onboarding; visible archives; and — increasingly — owning the infrastructure, or at least the member list, so a platform decision cannot end it.
The honest note: some communities should end. A community that has answered its question and has no new energy is better archived than kept on life support.