This is one of the most interesting things that I have seen on the Web recently. I came across it while researching a paper I wrote about political blogs and their effects on political discourse for POLS 41o - Politics and Technology at the University of Washington Summer 2009.
Shirky states that moment we are "living through is the greatest growth of communication in human history". Since we are living through such a moment, we are almost obliged to participate in it, hence this blog, and my sister-in-law constant pestering me to get a facebook page.
Shirky's lecture was given at the US. State Department in Washington, DC this June. It is over 17 minutes long, but definitely worth watching.
Link is here.