The paper presents an empirical study of user involvement in developing a technical standard for a scientific community's information system project. The case illustrates how multiple perspectives are involved when considering the user role in practice. The case presents a situation where both developers and users were pre-defined in the design and development phases of the standard as homogeneous groups of actors. Groups of actors changed to become more heterogeneous and 'fluid' in the deployment and implementation phases, thus forming 'webs of developers' and 'webs of users'. Detailed analysis of the process in its entirety shows the blurredness of boundaries between 'developer' and 'user' categories and roles, and reveals challenges at social and organizational levels. Three models pertaining to the system development process are presented in order to illuminate differing perspectives on the user and on the development process itself. The paper draws theoretically from information systems, social informatics, and science and technology studies. The research contributes to a deeper, interdisciplinary understanding of 'the' user, of multiple roles in systems development, and of dynamic sets of user–developer relations.