«Comunicazioni sociali», 2017, n. 3, 462-472 © 2017 Vita e Pensiero / Pubblicazioni dell’Università Cattolica del Sacro Cuore NICOLETTA VITTADINI* SOCIAL MEDIA: TRUTH WILL OUT, EVENTUALLY Abstract Since 2013, when the World Economic Forum mentioned in its annual report the “global risk of massive digital misinformation”, situating it at the centre of a constellation of technological and geopolitical risks, the issues of truth in digital communication and fake news have become a key area of academic research and public discourses. Misinformation is often described as the widespread diffusion of intentionally false informa- tion or of satirical contents. Nevertheless, misinformation has been described also as the diffusion of “unsubstantiated rumors, whether intentional or unintentional” 1 that circulate online, contribut- ing to a sort of collective credulity 2 . The article will focus on the latter typology of misinformation based on the diffusion of unsubstantiated rumors resulting in a “shared and believable truth”. In particular, the article will describe how the peculiarity of diffusion fows in social media, the homophily of social networks and some social media logics affect both the spread and the likelihood of misinformation. Special focus will be placed on the question of trust in social media and the evolution from a systemic trust in newsrooms to a predominance of the so-called affective trust given not only to charismatic fgures (horizontal or vertical opinion leaders), but to ordinary people or friends and friends of friends.The paper will also take into account the role of some crucial characteristics of 2,0 com- munication: the programmability of contents 3 and popularity logic 4 . The description will be based on the review of existing literature on trust and credibility and on information diffusion models in contemporary social media applied to a case history from November 2016 in Austin, Texas, which also became a news story for The New York Times. The case history will be used to exemplify some of the processes described. The fnal goal of the paper is to describe how the truth in social media, eventually, is the result of the interaction of specifc models of information circulation and the evolution of the attribution of trust. Keywords Social media; trust; post-truth; credibility; digital media; shareability. * Università Cattolica del Sacro Cuore, Milan ‒ nicoletta.vittadini@unicatt.it. 1 A. Bessi et al., “Viral Misinformation: The Role of Homophily and Polarization”, in WWW 2015 Com- panion - Proceedings of the 24th International Conference on World Wide Web, Association for Computing Machinery Inc., 2015: 355-356. 2 M. Del Vicario et al., “The Spreading of Misinformation Online”, Proceedings of the National Acad- emy of Sciences, 113, 3 (2016): 554-559. 3 Z. Papacharissi, P.L. Gibson, “Fifteen Minutes of Privacy: Privacy, Sociality, and Publicity on Social Network Sites”, in Privacy Online Perspectives on Privacy and Self-Disclosure in the Social Web, edited by S. Trepte and L. Reinecke, Berlin-Heidelberg: Springer, 2011, 75-89. 4 J. Van Dijck, The Culture of Connectivity: A Critical History of Social Media, Oxford: Oxford Uni- versity Press, 2013.