During the first protests of the 15M (also known as the movement of the “indignados”), and as information regarding it spread on Twitter, thousands of Spanish users turned to this medium to stay updated. The social networks were used by 15M to organize and disseminate information on the demonstrations, often in real-time. This article is a case study examining some journalistic uses of Twitter during this period by the 15M in Catalonia, who considered the occupation of Barcelona’s main square (Acampada de Barcelona) to be one of their most important acts. The aim is to explore the newsrooms’ journalistic routines on Twitter and if these produced a hybridization of functions between journalists and users. We conducted interviews with journalists from the main Catalan newsrooms and also analyzed the content of tweets posted between May 15 and June 19, 2011, a period known as the “explosion of the movement.” The results of this study suggest that, motivated by a pressing need for information on what was taking place, journalists turned to Twitter to find new sources, particularly within the 15M network, con- sisting of nodes in the camps and on Democracia Real Ya, the platform which summoned people to participate in the protests of May 15, 2011. During the 15M, journalistic routines took root which went beyond the rationale of access and credibility of information sources which were previously the domain of news agencies and other media, bringing about a new form of journalism that allowed professionals to give more amplitude and depth to news and information regarding the 15M. This phenomenon highlights the necessity to rethink the models in terms of participatory journalism, where social media and certain traditional journalistic functions may be performed by other users, including strangers, acting from outside the newsrooms.