ICQ Active Lists are groups of ICQ users, ideally with similar interests, who communicate with each other on a broadcast basis. Sending a message to an Active List will broadcast the message to all members of the group, not separate individuals. Active Lists are run by ICQ users; anyone can operate an Active List. All that's needed is the Active List Server software to create and manage Active Lists.
You can search for them by going to the Services menu and selecting the ICQ Active List. You have the options of Finding an ICQ Active List, or Showing the ICQ Active Lists you are subscribed to. Search by List ID, List Title, or List Category.