Social Networking Opens Infinite Possibilities for Communication
Facebook (and other social medias) are great tools for connecting people. Facebooks groups and events features could help groups communicate and the event feature can help people congregate.
Also, Twitter is often used as a crisis notification system
In a situation where the government is either unable or unwilling to get involved, social networking allows citizens to communicate and organize. In the situation where social medias are blocked by the government, anonymity softwares (like Tor) can be used to access social media still. Also https connections make it difficult for the government to track and intercept communications.
Here is an interesting video on the subject (unfortunately, not on YouTube or Vimeo):