The UGC (User Generated Content) revolution of Web 2.0 brought the application of this new paradigm into the enterprise and professional environment. This phenomenon is called Enterprise 2.0 and in these last years has drawn the attention of many experts in the fields of organization and knowledge management. In this context, Wiki systems and other social networking applications represent an important shift on the way in which people work: at the opposite of other previous IT technologies in this field, the Enterprise 2.0 is not about simple devices of office automation, but requires (and brings to) a dramatic organizational culture shift. In particular Wiki offers new possibilities and opportunities in order to exploit in a more effective way the entire potential of the collaborative work coming from the active participation of all the individuals that are present in a workplace. This dissertation wants to contribute to the current debate on the cultural shift that the introduction of this tool in a workplace is able to produce: we will see that, for a Wiki or any Enterprise 2.0 tool being effective it has to activate a virtuous circle able to create new knowledge...