I’m the supervisor of Michela Ferron, PhD student at the Center for Mind/Brain Sciences of the University of Trento and working with me in the SoNet group of the Bruno Kessler Foundation.
Her project is on formation of collective memories in Wikipedia and she just put up an interesting blog I suggest you to check. You find it at http://empiricalmemories.wordpress.com.
Below a video showing some comments posted during the fifth anniversary of September 11 attacks and during the first anniversary of the Virginia Tech massacre (occurred on 16 April 2007) on the related Wikipedia talk pages. But on the blog there is much more.
500 million people share their lives on Facebook, incredible eh? (see this blog post by Mark Zuckerberg).
For the occasion, Facebook launched Facebook Stories (http://stories.facebook.com/).
“Facebook is all about the individual and collective experiences of you and your friends. It’s filled with hundreds of millions of stories.
On 12th Febraury 2010, I made the following picture: at that time Facebook reached 400 million users and, if it was a country, it would have been the third country in the world. Today, 17th September 2010, it is at 500 millions. Anyway it will take some time before becoming the second largest country in the world, considering India has more than 1 billion citizens.