Thoughts on social network services

Reading about "The net and real costs of free" on BBC, reminded me of some old theories I had. It all comes down to the question whether a service should be centralized or distributed. The current killer services like Facebook and Piratebay, are examples of centralized services. All services with these providers require a connection to their respective servers. At the same time, the main problems associated with, for example, Facebook, is that it stores your private data on a central server. Likewise, Piratebay is seen as the distributor of copy protected material, even though it doesn't store the data itself, but only links to users storage spaces. So Piratebay gets the blame for the users illegal actions, because it stores sensitive data on a central server.
The question is then clear; would it be possible to generate the same services in a distributed manner, where the sensitive data would be stored only locally, or at least, at an operator you can choose yourself? In other words, would it be possible to design a distributed system with the same services?
If we take a look at another well eshtablised social service, perhaps we can find a solution. For example, let us look at telephone services or postal services. All data is stored locally, connections are relayed in a standardised fashion, privacy is protected by laws and we can, to some extent, freely choose an operator. Perfect. These eshtablised services avoid all the problems we face with the newcomers.
I do think that similar operation principles would be possible to organise also among the social network providers. All that we would need is a standardised communication interface. This is not a trivial task (as it is always with standardisation), but manageable.