This article is part of the studies of the Sustainability Assessment Center (NIPAS), to analyze Curitiba's social capital, expressed in the Colab digital social network. Colab is a social network accessible through its own account or Facebook. Its role is to provide citizens with spaces for interaction with public authorities or to publicize problems, proposals, and evaluations on aspects of cities. Thus, the research question arises: What is the social capital expressed in this social network? The methodology involved cataloging all Colab data, categorizing it according to the analytical model, and characterizing social capital. The results show that males aged between 30 and 49 interacted the most. Inspections prevailed among the three categories of Colab, inspection, proposals, and evaluations. This demonstrates that the expression of social capital is limited to occasional acts of dissatisfaction about the municipal public authority’s performance. In this case, the predominant themes are related to driving, such as parking, traffic signs, and road problems. About the macro categories of social capital, the interactions can be framed in “set of norms and values,” “citizenship,” and “sense of belonging”. The main conclusion is that although Curitiba is a city famous for its collective transportation, the predominance of social capital expressed in Colab is related to the automobile.