In this paper, we describe a new concept about a virtual environment on networked computers to support distributed collaborative work. We focus explicitly on tools to enable informal (casual) communications in contrast to most of the existing approaches of groupware applications. The establishment and maintenance of personal relationships is as indispensable in a virtual environment as in a physical environment, because the personal relationships lead the acquirement of new communication channels and the probability of future joints. We describe the concept of interactions in a virtual environment and two experimental tools for the one shared space in this virtual environment. These tools provide the opportunities for spontaneous, informal encounters and interactions with other people who have logged in the same networked computers, in order to support the formation and maintenance of personal relationships.