Power relations are a major concern in participatory design (PD). We explore how power relations are played out in a commercial collaborative design project that has not been influenced by PD techniques or interests. The case reconfirms many of the underlying principles of PD in handling power. At the same time, our Foucault-inspired analysis of the contextual dynamics and hidden power structures in user practices suggests certain extensions and improvements to the analysis of power relationships in PD projects.