Leonardo Sanna has been a contract doctoral student at the University of Modena and Reggio Emilia (Italy) since November 2018, where he has been working on the analysis of Big Data from a semiotic perspective. His research focuses on a combination of quantitative and qualitative methods for social media analysis. Currently, he is studying, on Facebook, the two phenomena known as "filter bubble" and "echo chamber". In particular, he works on the data of the FBTREX group.