1. A method for facilitating user collaboration and communication in a visual mapping system, the method comprising: tracking user presence in individual topics in the visual mapping system, wherein an individual topic is an individual hierarchical node within the visual mapping system that can be edited by a user and wherein user presence is only tracked for users that are online and that have selected a topic in the visual mapping system; displaying to an online user a visual map and an indication of any other online users' presence in individual topics in the visual map, wherein an indication of another online user's presence in an individual topic means that such other user has selected the topic and wherein the indication of user presence in the topic is displayed in connection with the topic; and providing an interface in the visual map through which the online user can initiate communications with any of such other online users.