Tim O'Reilly on the social network operating system. Some good points on the importance of identity and interop of addresses to people.
However, all this talk of YASN-as-address-book is missing the rest of the picture. YASN-as-platforms are not just a convenient way to manage your contact information. They are *also* a way for you to manage social-networks ... which means controlling access.
Not just, as O'Reilly says, allowing your YASN to see into your company directory and see that a potential contact works for you, but to create a company by inviting someone to be your employee in the YASN - with the social-network-operating-system handling all the financial, HR and legal issues that that entails.