A revolt or protest succeeds only if sufficient people participate. We study how potential participants’ ability to coordinate is affected by their information. We distinguish four phenomena that affect whether information either encourages or inhibits protests and revolutions: (i) Unraveling: When agents learn about each others’ types, some are discouraged by meeting partisans of the status quo. This can unravel, as even confident agents realize that enough supporters will be discouraged to preclude a successful revolution. (ii) Homophily: Learning someone else’s type under homophily is less informative since that individual is more likely to be similar to the learner. This can lead people to be less confident of a revolution, but can also stop potential unraveling. (iii) Extremism: Meeting other protestors, and seeing pilot demonstrations or outcomes in similar countries, reveal not only how much support for change exists, but also from which constituencies it emerges. This can undercut a revolution if factions differ sufficiently in their preferred changes. (iv) Counter Demonstrations: partisans for the status quo can hold counter-demonstrations to signal their strength. We also discuss why holding mass demonstrations before a revolution may provide better signals of peoples willingness to actively participate than other less costly forms of communication (e.g., via social media), and how governments use redistribution and propaganda to avoid a revolution.