Abstract : Internet artwork no longer refers to the concept of a finalized object, but rather to a dynamic process, a collective, open, and interactive device. Due to the increasing sophistication of tools, its design now requires hybrid skills. The necessary cooperation with computer analysts in order to create suitable programs thus brings about a status change of the artwork and the author. This paper presents an ethnographic case study of cooperation between a computer analyst and an artist. It is aimed at understanding the processes of shared design, negociated authorship, and artwork appropriation. From an analysis of the means of communication, of various technical media and "intermediary tools", we focus our attention on role allocation, task sharing, and artwork appropriation as it is modified throughout the creative process.