We describe a study of the impact of visual traces on the behavior of groups of users in Chat Circles, an abstract graphical chat room. The results indicate that traces, which appear in the chat space when users move or speak, change the way people position themselves relative to others and the way they move around the space. Traces also facilitate more expressive uses of participants� avatars, such as intimidation or showing agreement. Additionally, we consider differences in positioning and communicating between dyadic and larger groups in the chat room.