Since the seventies, in Western democracies, communication technologies and current social networks have attracted academic debate on the ability of these devices to promote an extension of the public sphere. The recent launch of Twitter, as well as other social networks, has produced an extensive discussion about their ability to promote the different dynamics of public participation to the mediated public space. This study seeks to explore the discussion on topics involving Spaniards in the digital public sphere, looking specifically at the participation in Twitter and two digital newspapers: elpais.com and elmundo.es. Through an analysis of their quantitative and qualitative content, 633 comments published on both Spanish most read online newspapers, and on their social profiles on Twitter have been studied. On the second phase, 240 Trending Topics have been collected, and their correlation with the themes of the barometers of the Center for Sociological Research (CIS) has been analyzed. Our research suggests that Spaniards do not generally discuss about their political concerns on Twitter. The main themes listed in the CIS Barometer -immigration, education, social issues, the government and individual parties or politicians, etc.-correspond to the topics registered in the online newspapers debate, but not in the social network. In general terms, the discussion of the Spaniards on Twitter is focused on soft news and the argumentation of their opinions is rather limited.