The work of this thesis focuses on the issue, often debated, of the “collective production” of knowledge, which for more than 40 years has been taking shape in contemporary media, characterized by the centrality of computers as a tool of “knowledge sharing” and as a “relational instrument”. In particular, the thesis discusses the collective production of knowledge in its online dimension, and specifically, inside the Wikipedia project, as an emblematic work in the treatment of this argument. Beside in-depth empirical research inside the Wikipedia community (“virtual ethnography” combined with “participative observation” in meetings, and offline interviews combined with interviews directly on the net), we trace a complex route from the first steps in the phase of social construction of the PC, to critical analysis of the production model and social ensemble, which comes closer to that observable within Wikipedia: that is to say, open-source, analyzing in particular the thoughts of its two main theoreticians: Richard Stallman and Eric Raymond. Then we look at the interventions that best seem to contribute to clarifying the socio-structural form sustaining the cooperative production of knowledge on the net: that is, with the structural theory of networks and emerging systems, as formalized by Albert Làszlò Barabàsi, and with the theories of complexity and emerging systems, at least as revealed in the field of human sciences. Starting from this theoretical frame, we came to an original result in the research sphere, recognizing in the Italian edition of Wikipedia a hybrid model, on one side recalling the dynamics of emergence and of complex systems, on the other presenting more typically communitarian aspects, such as have been described in the vast literature on virtual communities.