Just googling for “facebook openid” yields lots of results, all praising Facebook for adopting OpenID technology. Yeah, this is cool, but how can I really use it??? Facebook’s help system doesn’t have anything on this subject either.
Finally, I have found this post which explained what I needed to do. Basically, when you are logged into FB, just go to the following URL:
and add your OpenID under Linked Accounts. Just like the author of the post pointed out, the only benefit is that it allows you to automatically log into Facebook as long as you are already logged into your OpenID provider.