Let's say there are several users on your site with name 'Mike'. Now as I start typing 'M..i..k..', the system starts offering suggestions for possible users I'd like to tag. Can this list be filtered on the basis of users who're most active? Because these users are likely to be tagged often.
On our board, there are several users with name 'Abhishek' - one of the common names here in India. If I want to tag our moderator 'Abhishek', he's displayed at the bottom of the suggestions list, even though he's the only one who's active and gets tagged frequently.
Or even better - most frequently tagged people may be displayed first in the list - provided the first three letter match their usernames.