Collaborative Virtual Environments, such as multi-user domains MUDs, chatrooms, or three-dimensional graphical environments, provide a common space for people to interact in, independent of geographical location. In this chapter, we examined how the different metaphors used to represent two-dimensional and three-dimensional environments might influence interpersonal behaviours. We focused on behaviours related to navigation and positioning: 1) proxemics, the maintenance of personal space, 2) the signaling of private space, and 3) the effects of crowding. We discovered that the design of the three-dimensional space offer sociopetal spaces that encourage interaction, make clusters of actors easily visible, and provide cues so that people maintain a sense of personal space. In both environments, adverse reactions to crowding occurred. We suggest that differences in interpersonal behaviours may be influenced by an embodiment (avatar), design features of the space, and the number of other actors present. In a three-dimensional environment, these factors appear to influence navigation and positioning in the environment.