Cool Tip of the Day 10: Manage Your Contacts and Contact List
One more tip from Office Communicator team and this one is about the contact list management.
Your Contact List is a list of co-workers, family, and friends with whom you communicate most often. When you first install Microsoft® Office Communicator 2007 R2, you must build your Contact List.
Read more at source: http://communicatorteam.com/archive/2009/04/03/572.aspx