Back in 2010, Malcolm Gladwell famously predicted that the revolution would not be tweeted: online networks, he argued, are to collective action what the road is to travelling strangers: a space for fleeting connections; interesting, perhaps, but too feeble to make a traveler want to change course. As fate would have it, his forecast was published just a few weeks before Tunisia started the chain reaction that came to be known as the Arab Spring: during those weeks of turmoil and struggle, social media was the canvas where the story of the revolutions was projected and narrated by protesters themselves.

Since then, and as other protest tides have come and gone, scholars and pundits have been debating whether social media plays a significant role in the organization of collective action. Movements like the Indignados in Spain, Occupy Wall Street in the U.S., the Outono Brasileiro in Brazil, or the Umbrella Revolution in Hong Kong have had an overwhelming presence in online networks, which offer the only visible architecture to what is an elusive form of decentralized coordination – the key, some would argue, to understanding the logic of “organizing without organizations.” Many commentators, however, still claim that social media offers a poor reflection of real engagement, a form of feel-good activism that has barely any repercussion beyond showcasing a pretension of being involved.

In a paper published Monday in PLOS ONE, which stems from a collaboration between the Social Media and Political Participation Lab at New York University and the Research Group in Digital Media, Networks, and Political Communication at the University of Pennsylvania, we contribute to this discussion by casting empirical light on the role played during protests by peripheral participants, that is, the social media users that critical voices would identify as the “slacktivists” in the network.

Our analyses focus on the information dynamics that characterize collective action events, especially as they compare to the communication patterns that emerge in other non-protest related contexts. We analyzed the communication networks that arose in Twitter during the 2013 Gezi Park protests in Turkey, and the 2012 United for Global Change campaign, which was led by the Indignados (Spain) and the Occupy movements. These networks are all dominated by a clear core of highly engaged users, a minority in the overall network that generates, nonetheless, a substantive fraction of all communication.

Since these networks are based on retweets, we can trail information traveling from the core of highly committed participants to the fleeting periphery formed by occasional contributors. On a per capita basis, these peripheral participants are each adding very little to the exchange of information that is of value; but of course, their power lies in their numbers: there are so many more of them that, on the aggregate, they generate a higher volume of information than the minority of core participants and are thus able to increase the number of Twitter users exposed to information about the protest. In other words, without peripheral users, the reach of core protesters would be greatly diminished.

To quantify the impact of this critical periphery, we calculated the decrease in overall reach that eliminating low committed participants would cause. To do this, we progressively peeled the outer layers of the network (i.e. the peripheral users), removing them as you would remove the leaves in an artichoke to uncover its heart (i.e. the core of highly committed participants). What we found during this removal process, illustrated in the figure below, is that the periphery holds the key to maximizing audience reach: without the periphery, the voices of the core would be noticeably soundproofed.

Most importantly, we did not find these dynamics in the context of other events (i.e. discussions about the minimum wage, and the 2014 Oscars ceremony, our two benchmarks for comparison). What this means is that protest networks exhibit a structural signature that differentiates them from other types of communication: they rely on a division of labor between core and peripheral participants. These two types of actors engage in important synergies that are fully disregarded if we only sneer at slacktivism labels.

When we think about social movements, we tend to envision leaders pushing the movement forward; but without followers, there is no movement (or leaders, for that matter). Online networks have made it easier to capitalize on the small contributions that the many are willing to make in support of the few that are highly committed (those praised by Gladwell in his critique of social media). The most important resource for protesters is public attention: without it, their actions (and the risks they take) are little more than invisible. Granting this sort of visibility used to lie in the hands of the mass media; now it is also in the hands – as our results show – of the critical periphery.

Sandra González-Bailón is an Assistant Professor at the Annenberg School for Communication, and the Leader of the Research Group in Digital Media, Networks, and Political Communication at the University of Pennsylvania. Pablo Barberá is a Moore-Sloan Fellow at the NYU Center for Data Science and, beginning in 2016, will be an Assistant Professor of International Relations at the University of Southern California.