The unrest unfolding in Iran is the quintessential 21st-century conflict. On one side are government thugs firing bullets. On the other side are young protesters firing “tweets.”The protesters’ arsenal, such as those tweets on Twitter.com, depends on the Internet or other communications channels. So the Iranian government is blocking certain Web sites and evicting foreign reporters or keeping them away from the action.
http://nytimes.com/2009/06/18/opinion/18kristof.html