Communities on the Internet have developed to the stage where they are no longer a mere "virtual existence". Though these network communities have little to do with "real society", they are nonetheless a very real existence as they have a substantial and firm effect on society. To enhance the activities of network communities, utilization of IT tools is indispensable. However, design and development of community-oriented tools is not an easy task because tools should reflect the characteristics shared in the communities, which never cease to change. In this paper, we propose three aspects to characterize network communities: role, rule and tool. We will also introduce the interpenetration of these three aspects through the activities of the VCOM project, which is driven by Keio University. Finally, we discuss the indispensable characteristics of IT tools for network communities, which are regarded as having an important role to play as a real existence in the future society.