The notion of boundary objects has been a significant topic within the field of Computer-Supported Cooperative Work for some time. The idea that certain shared objects, artefacts, or representations may mediate between or serve the purposes of different communities of practices has been a powerful notion and has been useful in understanding discovered phenomena in field and case studies and in designing technologies and applications. Boundary objects has travelled far and wide as a concept. However, its success in its mobility has also been its problem – inexactitude. Boundary objects may be digital, textual or material, they may be static or dynamic, they may be shared amongst local or distal practitioners, they may be used by distinct groups or simply collaborators with different perspectives or access to information and they may be used for distinct activities or be part of a workflow. Their range is large. Other concepts like mediating or intermediary objects also occupy this territory. In light of this background a workshop was held at Coop 2010 in order to examine the territory covered by these concepts and to see whether we could loosely classify such research under different dimensions or whether it was important to refine or discard these concepts. The workshop had empirical, theoretical and technology contributions and was productive in mapping out the territory and finding ways to compare and contrast a diverse range of work within this domain.