  Pervasive personal communication technologies offer the potential for
important social benefits for individual users, but also the potential for
significant social difficulties and costs. In research on face-to-face social
interaction, ambiguity is often identified as an important resource for
resolving social difficulties. In this paper, we discuss two design cases of
personal communication systems, one based on fieldwork of a commercial system
and another based on an unrealized design concept. The cases illustrate how
user behavior concerning a particular social difficulty, unexplained
unresponsiveness, can be influenced by technological issues that result in
interactional ambiguity. The cases also highlight the need to balance the
utility of ambiguity against the utility of usability and communicative
clarity.
