During the last two decades, designing for usability has been the focus of attention when developing computer systems. However, the dynamic nature of human use of computer systems has meant that designing for usefulness or fitness for purpose is increasingly becoming the primary concern for systems developers. Central to this concern are issues underpinned by the social structure of the context in which a computer user operates. Within the field of Human-Computer Interaction (HCI), this situation led to a search for appropriate theories for conceptualising these design concerns. Whilst...