Sorry not to make it clear enough the function is something that is being used on the forum of World of Warcraft all ready, the admin sets the notification not the user. If a official response is made by a blizzard employee then an official icon is set before the post so you can see that some one responded to that topic that is working for Blizzard.
For a example look
here every topic where
is in front of is a response of a employee of Blizzard. When you press the icon you will be taken to the response of that employee.