It makes plenty of sense to me - currently Facebook, Twitter, etc. control all of your data. Imagine if there were one big web company which controlled all the servers, and you had to create web pages by logging into it. How much less useful would it be? Would as many programmers work on it?

<plug> I've actually started something similar as a side project, although I'm approaching it from the other end - build a system and then have some sort of spec. The idea is some sort of OpenID/OAuth setup to allow people to friend each other from different servers.

Very, very early days at the moment, so there's no code, but the manifesto is up at http://openf.oarsum.com/ </plug>