[lrvick]

You cannot use your gmail credentials to login to yahoo, but you can communicate with anyone from yahoo with your gmail account.

Similarly servers do not share credentials, but you can follow people no matter what server they are on.

[jrnichols]

It's finding people to follow that are on different servers. That's the thing. A lot of servers have their content for users only, and if you don't have an account on those servers, you don't know who to follow.

there's a lot of chicken & egg issues still going on. I think it'll get better as more people put their info on their web pages, though.