If you think you really made a difference by overlaying your Facebook profile with a French flag, take 10 seconds to sign an online petitition or retweet a celebrity who matches your beliefs about science, you are a "slacktivist" - an activist who doesn't really care enough to do anything worthwhile.

Policymakers dismiss you smf friends don't take you seriously as you flit from cause célèbre to  cause célèbre, but you might be making a difference after all.

Getting social media buzz, which may translate into mainstream media buzz, which may translate into policy talks, requires critical mass. If, as it is claimed, it only takes ten percent to create an inflection point, it won't really matter if groups like Natural Resources Defense Council or Union of Concerned Scientists are manufacturing buzz by mobilizing slacktivists, it still counts.

A paper in PLOS One by humanities scholars analyzed tens of millions of tweets surrounding a few specific social protests: 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.

Using location data embedded in the tweets, the researchers were able to differentiate between the people who were physically at a protest site versus those who were spreading the message from afar. They also looked at the senders' networks to construct a model of how information flowed and spread during the protest.

They conclude that Twitter is not as pointless as critics contend. In October 2010, Malcolm Gladwell argued in The New Yorker that "the revolution will not be tweeted", a dismissal of slacktivists who create the appearance of buzz on social media without any substance. Real movements for social change, he argued, have a committed, disciplined central authority. Online social networks with their weak ties and decentralized structure can't achieve change. That is why the "divestment" movement, getting universities to dump fossil fuel holdings, has been a failure. It's a social media invention.

Some assumed Gladwell was debunked because the Arab Spring protests began just a few months later, but it actually met the criteria for a real movement. It had a real centralized authority, which turned out to be militants even less interested in democracy than the groups they were overthrowing, but the perception to advocates was that Twitter could play a significant role in modern protests, with some observers even claiming it is the key instrument for organizing any modern protest. 

So social media 5,000 miles away leads people to risk their lives? No, it makes the dead people have a better chance of getting international attention. 

The researchers also looked at millions more tweets surrounding two non-protest events -- the 2014 Oscars and a year-long debate about raising the minimum wage in the United States. What they found were clear differences between protest and non-protest communication networks.

Protest networks show a division of labor where there is a small minority active at the center, generating most of the messages, photos, and content. Meanwhile a much larger group -- 'the critical periphery' as the researchers describe them -- amplify and echo the messages from the core group. In many cases, these 'slacktivists' may retweet only one or two messages, but in aggregate, their actions served to double the reach of the core protesters.

It means marketing groups at activists groups who want to turn the knobs of social media to give a protest resonance need to recognize that both matter. For example, marketers are obsessed with identifying and courting influential people in order to make products, content, and ideas go viral. But that can be hit and miss, especially if there is no periphery to echo them. What does seem to be true is that slacktivists alone accomplish nothing - it's still hollow buzz.