in backlog: https://trello.com/c/Ucgzd76H

Well, should we send a notification to the author of the parent post of the new reply? Due to our limited threading depth, the reply's parent may actually *not* be the one you replied to (if it was already at max depth)

To illustrate:

Post 1
    > Post 2, in reply to post 1
        > Post 3, in reply to post 2 (this is at max depth)
        > Post 4, in reply to post 3 (but really, it's a reply to post 2,
      since 3 was already at max depth)

Also: when someone creates a topic/post, he's automatically subscribed. Not being subscribed at this point is a choice (has to actually unsubscribe). I assume if someone's chosen not to subscribe, we may rather not want to keep bugging him/her with notifications for new replies?

Related: we still have notifications for users that are mentioned, and if someone clicks "reply", [[User:Username]] is already prefilled. (related: I just noticed that when subscribed + when mentioned, 2 notifications are sent; do we want that?)

That's a good question. If somebody's chosen to unsubscribe, that probably means they don't want notifications about it. Maybe we should ping Nick, and see what he thinks?

In general, I'd say we don't want two notifications for the same action. A "you were mentioned" notification is probably a stronger incentive to click, so we may want to treat the general "somebody responded to this topic" as a duplicate.

The problem is: we're doing roll-ups with the general "somebody responded". So if three people responded on the thread, but one of them mentioned you, what do we show? I think this is a design review discussion; I'll bring it up there...

Bugs should be actionable and this one isn't. Nick/Danny can you chat with design raise a new bug explaining the desired behaviour?