It's like with the telephone networks. What good is it if you can only call 2 or 3 people. But if you can call anyone who has a phone than the value of telephone as a medium increases. The telephone then is the enabler of new possiblities in conversations among human beings. It's all about human beings and not about technology.
Websites are converstions just like Markets are conversations .
Without the coversation there is no action. Thanks to Doc of cluetrain fame for linking to my story on Merchants of cool.