[xMAF]

I had a friend who was in Egypt during the Arab Spring 2011 and he told me they have been organizing for the revolution since October 2010 using Facebook via groups to spread the idea to everyone also using events to organise the marches.

Note that the government to deal with this had all communications cut including landlines and started to pay attention to these groups and pages since then so it's safe to say that your government maybe on to you if you use public tools like Facebook.