My post on the Monkey Cage (the Washington Post’s political science blog) is entitled “Social media hasn’t boosted young voter turnout.” The post may have turned out a little rambly, but the point is to contrast some effective recent social movements that have been driven by social media (the Dreamers and marriage equality) with the completely flat turnout rate of recent midterm elections in order to ask about the advantages–and limitations–of social media for various kinds of politics. At the end, I pose four questions:

First, can the new media engage young people who start without an interest in politics, confidence, or skills? There is little sign that large numbers of formerly apolitical young people are being recruited into politics online, even if we define “politics” broadly to include consumer and cultural activism.

Second, we can point to impressive examples of videos, slogans, and images that “go viral” and make their creators famous and influential. But for every such case, there are many that go nowhere, being seen only by the maker and perhaps a few friends. What is the impact of being unsuccessful in a competitive online arena? Is repeated failure discouraging, especially when the rare successes are so widely trumpeted?

Third, the removal of “gatekeepers” (such as newspaper editors, TV anchors, and party elders) has made information freer. Anyone can create and share a video without permission. But the task of sorting reliable from blatantly false information has become harder. How will young people — and older people, too — learn to separate the wheat from the chaff?

Finally, can online social movements be sustained in the face of adversity? The ALS Challenge (in which people dump water on their heads to raise money for amyotrophic lateral sclerosis), has raised $115 million. There have been 10 billion views of the Challenge videos. That was an impressive burst of activity that probably far exceeded the goals of the organizers. But the Challenge faces no organized opposition and need not continue to achieve its purposes.

In contrast, the Arab Spring, also powered by social media, faltered when it encountered disciplined resistance. The events of Ferguson, Mo. in the summer have prompted much online organizing (some from the right as well as the left), but that attention may also fade. To make a difference on a complex and contentious issue requires lasting effort. Whether the new participatory politics can sustain political engagement remains an open question.