The federating theme of Web 2.0 applies to the most recent information technologies, one of the essential properties of which is extensive diffusion in the private and professional spheres. This article examines the corporate uses of Web 2.0, through an exploratory study of one of its most emblematic tools, the Wiki. The authors examine the processes of appropriation by individuals, and the effects of the organizational dynamics underlying them. The theoretical analysis and the plurality of the empirical data collected (observation of traffic, quantitative and qualitative study) underscore the diversity of the situations encountered. They also highlight the processes of adjustment between the various organizational and individual levels.