Over the past 20 years, the management of the decision-making processes has become increasingly complex. Decisions with a direct impact on the lives of citizens are no longer considered the exclusive prerogative of experts and politicians (Bucchi, 2006). Several attempts, both top-down, enacted from the institutions, and bottom-up, enacted by the citizens, have been made in order to widen participation. The internet has entered this scenario by opening new spaces for the exercise of citizenship. This Ph.D thesis tries to explore the issues described above in the specific case regarding the construction of a high-speed line (Tav) between Venice and Trieste. With the support of the literature on techno-scientific controversies, a methodological approach has been applied to the case study that brings together digital - research methods based on the actual characteristics of the medium (e.g. tags, links, likes....) and digitized methods - traditional research methods exported online (Rogers, 2010; Marres, 2012) with the aim to account for the multi-dimensional appearance that public participation takes in the context of a techno-scientific controversy and in particular to value even the forms of participation that tend to escape the traditional approaches to the theme.
