This chapter reports on advances made in the field of distributed systems technology for the computational support of CSCW applications, with emphasis on distributed synchronised applications (i.e. same time, different place). The main concepts are first recalled, and illustrated by the description of two CSCW platforms developed in Broadcast: NAVCOOP, based on a grouporiented communication layer, and CoopScan, based on software agents. Finally, the techniques for enhancing a legacy interactive application with facilities for distributed cooperation are discussed and illustrated by two examples.