I've been using StackOverflow since it was stackoverflow.org. Some time back in 2008, while I was working at MIPS Technologies, I heard about it and signed up.
Right now I am trying to figure out what is going on with all of the layers of non-coherent credentials that are floating around the world which have something to do with how I log in to StackOverflow.
If you can help me bootstrap without too much cost, i.e., you know of a document that explains all this (not just OpenID!), please let me know.
A great starting point would be a tool that tells me the credentials being used to get me to the Web site I am looking at.