Pervasive systems are composed of a large variety of networked smart devices that supposedly enrich the environment they are deployed in. The access to services provided by a pervasive system should be as natural and “unconscious” as possible. In a large number of cases, the available interaction modality seems to be more oriented towards showing off technological wonders rather than to the actual usability of the interface. In this paper we evaluate and compare two different versions of an information provision system deployed in two editions of a large fair. In particular, we will focus on the Human-Computer Interaction (HCI) and Computer-Mediated-Communication (CMC) points of view. The analysis of such case studies is essential to understand the social dynamics of groups of people remotely interacting. One can thus talk about social ergonomics, which together with cognitive ergonomics, sketch these contexts from a perspective of individual usability. This is characterized by rules and guidelines for an accurate design of the communication environments. Such discussions aim at the optimization of the interaction process in accordance with the goals of the information system, in terms of interfaces, user satisfaction, performance and efficiency produced by the correct CMC. The comparison we propose will allows us to infer some important conclusion that can be useful to anyone who want to develop and deploy similar systems within similar events.