The MEGATOPIC: public good, or public menace?

I’ve used this in the past. In my case, I also muted that category for all members and posted an announcement explaining how you can un-mute it if you’re interested in off-topic discussion.


Agreed. I think the following additional things should happen when a megatopic gets automatically closed:

  1. A continuation topic is automatically created. E.g. “What did you have for lunch today?” gets automatically superseded by “What did you have for lunch today? (2)”. This would work exactly like our Linked Topic creation, along with a closing notice linking to the new linked topic.

  2. If tags are enabled, the topics would also be assigned a generic tag.

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Eh, maybe – that’s institutionalizing a) the continuation of exactly the same thing, which might not even be the right call and b) bad topic naming.

Having zero friction here is, I think, the wrong call. How about something more like a hint:

This topic was automatically closed because it was super duper long, like seriously!

Feel free to continue the discussion in a new topic.

Where “new topic” is equivalent to pushing the new topic button.


Chances are if a Topic reaches 10,000 posts - 10,000 is not the natural limit. By closing it you are shutting down something that members, more than likely, want to continue.

Maybe just add a mod setting in addition to what @erlend_sh has said “do not continue topic if reaches threshold”. I would also add an admin setting too (I’d probably want to keep the max to what may be more optimal for the server - so maybe half that at 5K?).

Having said that, if simply auto-closing it is much easier to do - do that, as there’s plenty of other (more useful) things that your resources could go on :smiley:

The SitePoint vBulletin forums had a few “mega threads”. But they were not what I’d call discussions. A few were “game” threads which were more post-to-post where there was no presumption that anyone would read every post from first to last. And there was a catch-all Introductions intended to consolidate multiple “Hi, I’m new here” threads. There were also some “opinion” threads which were little more than a series of “I like __ best” with a sprinkling of substance here and there.

I guess whether or not a community wants non-discussion topics in its forum is up to the community. But in my experience and in my opinion any discussion that starts to get anywhere near “mega” has become full of tangential and repititous posts that make reading from first to last such a major task that it is highly doubtful anyone would do so.


The limit is already a site setting (and has been for quite a while). See auto close topics post count and auto close messages post count. If you are self-hosted you are free to change these settings as much as you wish. On hosting we’ve enforced the 10,000 post count setting globally (as Sam mentioned above), so that cannot be changed.


Revisiting this after a year, and after some experience with the philosophy of decentralized social networks, I have another way to frame the problem:

Discourse didn’t want to fix the performance problem because megatopics are trying to scale the software past the human limits.

10,000 replies is clearly arbitrary. But it’s also clearly way too many posts for a single topic. It’s just like the follower / following performance limits on Twitter-like platforms: if you actually need 100k followers, consider a blog instead :wink:


Megatopics are bad, part deux:

As someone relatively new to College Confidential and a parent trying to help a junior through the college admission process, I find these [megatopics] overwhelming. I’m overwhelmed by the generosity of people like doschicos to provide relevant information. And also overwhelmed with the length and complexity of these [topics]. I’ve found them hard to read and even harder to analyze for the purposes of moderation.


Megatopics are bad if you have a forum geared towards discreet tasks with finite ends. Open ended community discussions can easily hit 10k quickly while staying on one narrow subject.

I co-admin a forum with < 500 registered users that discusses news and current events and we hit the limit frequently. We are already halfway through our third dedicated topic for COVID-19, with multiple side topics as well. The second one had to be closed after only 21 days.

Having said that, even for us it’s not a huge deal to start a new one. While I’d prefer theoretically infinite topics to be available, it’s something we can live without if implementing it is a huge undertaking.

But I don’t think megatopics should be considered a rare edge case, nor should it be assumed they are always a bad thing. Some established communities even take pride in having single topics that are both huge and long lasting.


Megatopics are always a bad thing. Implies you need a real chat room.

These communities are dead and dying. They just don’t know it yet because they lack self awareness.


Same here with our COVID-19 topic. Had to close the first after 2 months, then start a 2nd - which we’ll close at the end of 1 month. We’ll be starting a new one each month as the number of posts seem to grow very quickly. To everyone’s credit, they (we) mostly stay right on topic with only a few posts veering off toward politics, but then this has been tightly woven into politics. We also have a COVID-19 topic strictly for Research being done, and one topic just for tracking the spread of the virus, # of cases/deaths, etc.
We keep our topics to a maximum of 1,000 posts. We are a small private forum, so that saves us from the dilemma others face.

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We’ve tried having chat rooms. Our users prefer your software.


My suggestion would be to evaluate chat products with the goal of integrating them seamlessly.

Ephemera doesn’t belong in Discourse.


You’ll need to be very careful here. Maybe have one ‘chat’ topic at a time and delete the old ones religiously, because there is an intense performance penalty to the server for every megatopic that continues to exist, and that penalty increases with every single pageview.

Best to integrate an actual chat tool though, per


Agree 100% with this. Sometimes they add value to the community, but not to the extent that it necessitates code changes IMO.


Could you expand a bit on this performance penalty? This is for closed and archived topics? Closing topics at 10k is fine, deleting them would be something else entirely.

My community loves Discourse and has been forum-based for over 15 years. They won’t use a chat room and they would react very negatively to having old topics deleted. If there is going to be a serious and growing performance issue from these topics simply existing then I am going to need to either render them out as static pages or migrate to another platform.

I realize our community doesn’t fit well with how you envision Discourse being used, but that’s the community I am responsible for and there are some changes I can’t force them to make. We’ve actually never been stronger as a community than we are now using Discourse. I would hate to have to move to a different platform when everybody is so happy with our current setup.


Megatopics need to be mostly hidden – even if they are closed and/or archived, the more users that hit a megatopic the worse your server will perform. Ideally the megatopics should be deleted so you only have one active at any given time? That’s my recommendation. The more megatopics you have the more risk you incur.

If you can throw a bunch of money at the problem you could massively overprovision your server and support more megatopics – but it’ll still impact median performance for all topics.


Even when a topic is closed it generates data, traffic and load.

Remember that every users read position is recorded against every topic. Every post can be liked, interaction with megatopics is still possible after they are closed, not to mention the amount of noise it can throw into your search results.


That still doesn’t explain why megatopics in particular cause issues. Why is one 10,000 post topic worse than ten 1,000 post topics? With the latter there’s the same number of total posts to be potentially liked or searched for, but ten times as many read positions and topics to be searched for. Based on your explanation alone, I would conclude that a greater number of smaller topics is worse. So there must be more to it.


Because you’re loading just one topic at a time. You can pick up 10 1000 one at a time without trouble, but picking up 10,000 at once is much harder.