Thanks to a link provided by Mark Roest, we have some further insite into the topology of the social media networks involved in the Arab Spring. Follow this link the full article over on Nature.

The recent wave of mobilizations in the Arab world and across Western countries has generated much discussion on how digital media is connected to the diffusion of protests. We examine that connection using data from the surge of mobilizations that took place in Spain in May 2011. We study recruitment patterns in the Twitter network and find evidence of social influence and complex contagion. We identify the network position of early participants (i.e. the leaders of the recruitment process) and of the users who acted as seeds of message cascades (i.e. the spreaders of information). We find that early participants cannot be characterized by a typical topological position but spreaders tend to be more central in the network. These findings shed light on the connection between online networks, social contagion, and collective dynamics, and offer an empirical test to the recruitment mechanisms theorized in formal models of collective action.

The network analysis shows that users at the core of the network are more likely to be the seeds of global chains of information diffusion.

The distribution of cascade sizes (Nc) suggests that only a few cascades percolate to affect most users, and that the vast majority die in the early stages of diffusion. (B) There is a positive correlation between network centrality, as measured by the classification of nodes in high k-cores, and cascade sizes, suggesting that users at the core of the network are more likely to be the seeds of global chains of information diffusion. (C) The nodes in the network arranged according to their k-core; node size accounts for degree centrality, and node color indicates the maximum size of the cascades generated by the user (users generating the largest cascades are depicted in orange). (D) Example of a global cascade affecting about 35,000 nodes. Nodes in blue are users who participated in the diffusion of protest messages; nodes in orange were exposed to the messages but did not send messages of their own. The darker the shade of blue, the earlier users joined the cascade as spreaders; the lighter the shade of yellow, the later users joined the cascade as listeners.

While this sort of analysis is useful, it would be great to correlate the form of these networks with the form or shape of the network (as I agued for in The ethics of network topology), and to examine the qualities of the conversational links  - which I talk about in an earlier post (Equality, and the structure of democratic networks).