I see all these subscription options under my profile but how do I subscribe to a discussion topic to get email notification?
I see all these subscription options under my profile but how do I subscribe to a discussion topic to get email notification?

So what is the purpose of this "Subscriptions" menu in Settings?

And under the "Notifications" menu in Settings, I see "Activity from Subscriptions". Is this dependent on what shows up in the "Subscriptions" menu? Right now, I am not even sure how to get anything to show up in the "Subscriptions" menu.