We report the findings of a field study of the enactment of ICT supported knowledge work in a Human Resources contact centre, illustrating the negotiable boundary between what constitutes the developer and user. Drawing upon ideas from the social shaping of technology, we examine how discussions regarding producer-user relations require a degree of greater sophistication as we show how users develop technologies and work practices in-situ. In this case different forms of knowledge are practised to create and maintain a knowledge sharing system. We show how as staff simultaneously distance themselves from, and ally with, ICT supported encoded knowledge scripts, the system becomes materially important to the project of constructing the knowledge characteristic of professional identity. Our work implies that although much has been made of contextualising the user, as a user, further work is required to contextualise users as developers and moreover, developers as users.