The former social network site for students now has become:
"Facebook at its core, is a profile and presence aggregator, channeling all of my online activity through one main hub, combining almost every online “social” tool that I use currently." (http://www.briansolis.com/2007/08/facebook-is-online-hub-for-connected.html)
More Information
The delicious tag at http://del.icio.us/mbauwens/Facebook
The Economics of Privacy at Facebook.