It's been the recurring thread in American politics since the "Turn on, tune in, drop out" and "state's rights" of the 60s.
Social media might be nurturing more extreme views by fostering more isolation from challenging beliefs, but one could also argue that it's exposing people to more of other people's views than ever before.
Social media isn't required for revolution, obviously, but it feeds antiestablishment movements more effectively than underground printing presses and independent radio did.
At least for the moment. Perhaps a new establishment will arise that's learned to control the Internet as well as previous establishments controlled other media.
Social media might be nurturing more extreme views by fostering more isolation from challenging beliefs, but one could also argue that it's exposing people to more of other people's views than ever before.