OK, it turns out I really can’t keep up with all TW activity 
Every category (as well as every post) has a per-user setting to control what you should get notified for.
I just set my settings for categories to be “Watching First Post”. That way, I’ll see all new posts, but won’t get a notification for every single reply unless I interact with a post.
I will always get notified if someone @-mentions me.
Hope that’s helpful for others in tuning your notifications.