This thesis investigates the interaction mediated by technology, from messages produced and shared by the citizens of the Rio de Janeiro on Twitter and Facebook, focusing on urban mobility, during their movements in traffic and in public and private transportation. The objectives of the study seeks to: i) perform an analytical examination of the activities and actions in the conversational sequence, describing how participants produce and interpret them; ii) analyze the roles that citizen and social network technologies play interactively in a multi participation framework; iii) reflect on how the activities and actions that arise from virtual conversation are related to urban social life. The study is based on the theoretical concepts of Conversation Analysis, in the virtual context, via new technologies, which inform about turn-taking, activities and actions, Interactional Sociolinguistics, in the scope of participation framework and participants roles in the production and interpretation of the utterances, and the studies of the social order upon urban mobility in big cities. The methodology is qualitative and interpretive. The data consist of public conversations from the social network pages of BRT Rio, Metro Rio, O Dia 24 Horas and SuperVia, where participants interact with each other and with the companies. The messages were selected according to the actions they implement, contextualized in the universe of urban mobility. The analysis of the data indicates: i) the arrangement of the turns in the unordered sequences of post demands new producing actions strategies on the organization of the interaction, and the expectations of the participants are defined from the choice of which previous turn they will perform an action in sequence; ii) ii) in these actions, different interpretations arise, such as requesting and providing information, notification, praise, thanks, complaint, suggestion, insult, criticism or non-response; iii) drivers and passengers play a collective role in interacting in this environment, where the participation framework becomes more complex by converting all participants into simultaneous and alternated potential speakers and ratified listeners , setting patterns of multiparticipative social organization of interaction. These new technologically mediated forms of communication, focusing on the urban mobility in a big city, update the concepts about face to face interaction models, the citizen s role in this process and the situated contemporary social phenomena.