Recently I have noticed for the first time a comment by a moderator which contained @@username. Previously I have seen something similar in chat - I know that the mods have superping in chat - the ability to ping any user, even if they were not present in that chatroom (so they are not pingable by regular users using @username.)

I have also seen that when a super-ping is used un chat, the syntax @@user-chat-id is employed. (Although it is rendered simply as @username.) So the syntax @@username naturally reminded me of a super ping.

I have never seen something like that in a post or in a comment - so this made me curious a bit.

Question 1. Do moderators have ability to notify any user in a post or in a comment? (Even in situation where the user would not be notify by the standard comment replies.)

It is natural to ask also this:

Question 2. Could implementing something like this be useful in some situations?

I will explicitly say that I am not posting this as a feature request - my personal opinion is that situation where something like this would help are going to be rather rare and there is always some kind of workaround. But since I asked whether such feature exists, this seems like a natural follow-up.