So I have used MyOpenID for years, ever since SO forced me to use it. In every situation where openId was an option I've used it in deference to connecting a google/fb account or creating a new user/pass. I have used it for countless websites. Literally countless. As in, I have used it everywhere and I haven't written down where I've used it, because if I go to log in and I see it supports openid I know that I used myopenid.
I also don't know much about the technical aspects of openID (though it sure sounds like an upskilling is about to be forced on me).
I have my own domain, and I'm happy to run openid through that, and I'm sure 10 minutes of google's time will make that setup plain.
What's not plain is how I migrate from myopenid to my own openid provider? Everything I've signed up with is attached to my xxx.myopenid.com url correct? So do I get to keep that URL somehow and point it to an implementation elsewhere? Or does every website that uses openid have to support migrating between openid urls?