How can I imitate Stack Overflows SSO? Particularly where it federates with serverfault.com?

Question

How does Stack Overflow\'s SSO work? ... whatever it is they are doing it seems to work for all sites in the network.

I\'d like to learn what Stack is doing so I ca

Answer 1

OpenID, One Year Later on SO blog explains how do they solve the problem.

Also, there is a post on the new Global Login Mechanism on the SO blog.