This paper focuses on the study of online epistemic communities, whose aim is to construct knowledge objects, such as open source software (OSS) and encyclopaediæ (Wikipedia). We aim to examine and expand on several issues that these communities raise for design ergonomics research. Our theoretical position is that these epistemic communities can be studied as new kinds of design collectives. Three lines of research are outlined concerning design processes and products. The first pertains to the various forms of participation in these communities, using work analyses. The second addresses the socio-technical mechanisms that support participation, in particular situation and social awareness support. Finally, the question of product quality is discussed. With respect to each research approach, a critical review of the literature and a research agenda for multidisciplinary research are put forward.