The account names used on the computers at Apple stores apparently follow a pattern, the script using that pattern creates all of the accounts possible at a store, then using an API available from AOL grabs the current status of that "username", and their user icon, displaying online or offline status.
The actual script doing the fetching and whatnot is very easy to read: http://www.lehnerstudios.com/stuff/applestorechat/applestore...