Malcolm Gladwell is cynical about the ability of social media to facilitate activism:
The platforms of social media are built around weak ties. Twitter is a way of following (or being followed by) people you may never have met. Facebook is a tool for efficiently managing your acquaintances, for keeping up with the people you would not otherwise be able to stay in touch with. That’s why you can have a thousand “friends” on Facebook, as you never could in real life
If Twitter is only identifying people with weak preferences for activism, the “revolution will not be tweeted”. But there is a second countervailing effect created by network externalities, studied in Gladwell’s book The Tipping Point. An individual’s cost in participating in a revolution is s function of how many other people are involved. For example, the probability that an individual gets arrested is smaller the larger the number of people surrounding him in a demonstration. Even if Twitter in the first instance does not increase the number of people participating in a demonstration, it does create common knowledge about where they are meeting and when. The marginal participant in the absence of common knowledge strictly prefers to participate with Twitter-common-knowledge. Now more individuals will join as the demonstration has gotten a bit bigger etc. The twitting point is reached and we have a bigger chance of revolution. Now, let me go to Jeff’s twitter feed and see what he is plotting in his takeover of the NU Econ Dept.