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”.
私も同じです。過去数ヶ月で多くのサブカテゴリを徐々に作成してきましたが、ようやく、全員にこれらのサブカテゴリへの購読を手動で設定してもらうよう通知する必要があることに気づきました。
私にとって最も明白な解決策は、トップレベルカテゴリの購読設定を、作成される新しいサブカテゴリのすべてに対してすべてのユーザーに複製することです。これにより少し過剰な購読が生じる可能性がありますが、メール内のリンクを通じて各ユーザーが簡単に修正できます。
それ以外では、Discourse は非常に素晴らしいです。