OK Dunk, If you go to your profile you will see a list of services you may subscribe to like Aim, MSN, Yahoo Instant Messenger, You own web site, and something called ICQ. All these items have there own Icons that you see on the posters window. Also there is a green dot which indicates if the poster is online or not.
When I signed up here in April there where several icons displayed that I didn't subscribe to, so I checked my profile and for some reason my email address was displayed on all The lines, so I had a full course of icons. I removed them and now only have the three icons.