I have two levels of categories in my forum. I would like to allow users to change their notification settings on the top-level category with an option to apply this setting to the sub-categories within the parent. This prevents them from needing to react to category changes by once again updating their sub-category settings.
I’m thinking something like a checkbox to enable the notification selection to apply to all sub-categories.
a main section may have dozens of sub-sections, it’s annoying to mute them all manually.
I think a modal would be better. That way when you change your tracking status, we say something like:
Would you like to apply this change to *all* underlying sub-categories?
You're currently Watching 2 sub-categories, and Tracking 1 sub-category.
This is what makes it a not-so trivial change though. A convenience feature like this one needs to communicate very clearly what it does, so that users don’t shoot themselves in the foot. No one wants to make a mistake in bulk 
If a clear UX path is laid out, we’d probably be open to a PR on this one.
Has anything happened in this area? My categories are still a bit in flux, and they might continue to shift. I would like someone to be able to set a notification for a main category, and have it apply to all sub-categories, even if new sub-categories get created later.
To me, conceptually, a topic that is in the “Main - Sub” category is also in the “Main” category. I expected that watching “Main” would notify me if someone created a topic in “Main - Sub”.
저도 마찬가지입니다. 지난 몇 달 동안 서브 카테고리를 천천히 많이 만들어 왔는데, 이제야 모든 사용자에게 서브 카테고리에 대한 구독을 수동으로 설정하라고 알려야 한다는 사실을 깨달았습니다.
제게 가장 명백한 해결책은 최상위 카테고리의 구독 설정을 새로 생성되는 각 서브 카테고리에 대해 모든 사용자에게 복제하는 것입니다. 이로 인해 구독이 약간 과도해질 수 있지만, 이메일 내 링크를 통해 사용자가 쉽게 수정할 수 있습니다.
그 외에는 Discourse가 정말 훌륭합니다.