One of the most important qualities related to the use of information systems is arguably the usability achieved in actual use-situations. Three central criteria for usability as reflected in contemporary definitions are the effectiveness, efficiency and satisfaction with which users can achieve specified goals. A problem with these criteria is that they are expressed in terms of achieving goals, which, at least tacitly, seem to be restricted to goals related to an instrumental view of information system use. In this paper, we discuss how the concept of usability can be understood and utilized within a social action context. Specifically, we address how communicative goals are related to the criteria of effectiveness, efficiency and satisfaction. We argue that, in order to understand usability, we must consider both instrumental and communicative goals, since their combination constitutes a fundamental part of the social action context in which systems are used. Both instrumental and communicative goals affect the way systems and use-situations are designed and conceived.