Todd Biske is an enterprise architect, a prolific blogger on SOA and other IT issues, and one smart dude. In a Dec 1st post on his blog he makes a great case for Facebook -- or something like it -- as an enterprise collaboration tool.
"In my opinion, viewing Facebook solely as a marketing/customer support channel is seriously limiting its use to an enterprise. The conversation should begin with an analysis of the communities that can be supported. Guess what? There’s a looming community with a very complicated social structure that exists within the walls of the company. Why can’t tools that are designed for enhancing communication and interaction between the social structures of society be applied within the walls of the enterprise?"