Networks: Tweetin’ ‘bout a revolutionDOI: 10.1038/srep00197An analysis of the role of online social networks, such as Twitter, in the growth and spread of social movements is published in the journal Scientific Reports. Twitter and other internet technologies are often said to have contributed to the rapid growth of many of the recent wave of popular protests — both in the Arab world and in Western countries, including the London riots in August 2011 and the ongoing Occupy movement. But there is little empirical evidence of the mechanisms through which these technologies disseminate calls for action and organize collective movements. Sandra Gonzalez-Bailon, Yamir Moreno and colleagues studied Twitter activity data for the period around the mobilizations in Spain in May 2011, which emerged as a reaction to the political response to the financial crisis. They examined the posting behaviour of over 80,000 users and tracked nearly 600,000 messages about the protests, analyzing the dynamics of recruitment to the movement and of information diffusion. The position within the network of early participants, who lead the recruitment process, tends not to matter, the authors report. More important is the position of the individuals responsible for disseminating the information widely and rapidly, who tend to constitute a small group of users close to the network’s centre. The authors caution that because they did not control for users’ demographic information or for exposure to offline media, further research would be needed to account for these factors and to eventually lead to meaningful predictions of future occurrences of mobilizations.