Rules:
Only applies to other people in the comments that you are commenting on, or editors of the current post.
Response must include @username that you are referring to, where "username" is a reasonable match to the user's current display name (as seen in the comments above yours).
There must be a starts-with, case insensitive match of at least THREE characters to the displayname. So @a and @ab will never match anyone or anything.
Spaces cannot be used to match, so if the person's display name is "Peter Smith" then just use @peter or @petersmith to match.
Matching is performed in reverse chronological order, so if there are five people named "John" in the comments, writing "hey @john, have you considered apples?" will match the most recent John to comment.
