I ask because this is a major hurdle with the Diaspora* model, in my opinion. I just created two accounts with the same username on different servers to test, and the fact that I could do that bummed me out a bit...

It's great that my data can be free, but if my account is tied to a specific host and I must make a separate, unique account with another host later then I'm still substantially locked in. Essentially, switching accounts likely means all my social connections will have out-of-date contact info, urls, etc. when I switch.

If, however, my user ID is global across the distributed network and there is a way to gracefully transfer my account/data/info to another server seamlessly (without my social connections even knowing/caring about it) then I think distributed social networks like GNU Social could be a game changer.