Well, I had an account at StackOverflow but recently I started to use my own domain names, with it's own OpenID. (Two domains, two OpenID accounts!) I already had two OpenID's linked to my account so I removed one, added my new one, swapped both ID's, removed the other and added my second, new ID. And poof! My new OpenID accounts are now linked to StackOverflow...
And then I also changed my name... :-)
But the Other StackOverflow sites don't recognise my changed account anymore. So on those sites I now have two accounts. I guess I have to do the same swapping on those sites too, but it's annoying!
Wouldn't it be more practical to allow more than two OpenID accounts? Or even an unlimited number of ID's?
The reason why I use two ID's is simple. One is used when I'm at work, the other when I'm at home.