You can enter your names for whichever IM services you may use in your profile, and the ones that you did so for have an insignia button that appears at the bottom of each post. If you wish to AIM someone, or perhaps merely learn their AIM name, you can click their AIM button.
EDIT: Also, threads like this get locked because they are polls. The Forum rules define polls as threads where a reply can be given in only a couple words. If you can't add any reasons for your answer, then it is considered a poll and locked.