How can we account for technology adoption and use within organizations without relying on preconceived notions of materiality and sociality, notions that inevitably lead us to favor either a techno-centric perspective or a human-centered perspective? In this paper, we argue that an interesting way to do this is to take seriously people’s matters of concern. This means two things: taking into account all the matters of concern that come to express themselves in conversations (whether related to tools, rules, documents, principles etc.) and not only the people who voice them; and showing how some of these concerns manage to matter more than others by speaking to, for, with, through or against each other. To demonstrate the theoretical and empirical value of this approach, we analyze two interactional episodes, taken from our longitudinal study of the introduction of a wiki at the French National Agency for Radioactive Waste Management.