Unlike physical or biological systems, human social systems are loosely-coupled in nature. Ambiguity and interpretation play important roles in human communication, Language is a key means of creaiing and maintaining shared realities through consensual processes. Consequently, an understanding of the interpretational nature of social interactions is required for the design of computer-mediated communication systems. Computerbased systems vary in their abilities to cope with the ambiguities inherent in social interactions; the mediation of "rich" social interactions with computer technology is often problematic. Some existing computer mediated communication systems are examined with respect to the issues discussed in this paper.