I signed into (and presumably registered with) askubuntu using my launchpad openid.
I'd like to also ask some questions on other Stack Exchange sites but keep all the accounts connected.
When I go to sign in at (for example) stack overflow, the openid options do not include askubuntu or launchpad. How can I ensure that any new accounts I create will be correctly linked? Should I register an account with the main stack exchange site first? I seem to already be a Stack Exchange user as I can click on "Network Profile", and this takes me to Stack Exchange where I can see my stats, but I don't seem to have an actual log in to Stack Exchange.