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”.
我也是。过去几个月我们一直在陆续创建许多子类别，但直到最近才意识到，需要通知大家手动设置对这些子类别的订阅。
对我来说，最显而易见的解决方案是：将顶级类别中所有用户的订阅设置，自动复制到每个新创建的子类别中。这可能会导致一些过度订阅，但任何用户都可以通过邮件中的链接轻松进行调整。
除此之外，Discourse 非常出色。