In 2009, Facebook introduced a very cool feature to automatically log you in if you're already authenticated against a list of authentication providers. This feature is based on OpenID 2.0 protocol.

Once you got it set up, log in to GMail, Yahoo Mail or Stackoverflow with OpenID (2.0 that is) account and you supposedly don't have to put in your username and password anymore into facebook. It just takes you right in.

What's odd though, it seems that only the following two OpenID providers are working for me: Google, ClavID.

As described here, Facebook is relying on OpenID ‘identifier select’ mode which neither MyOpenID nor ClaimID seem to support. So don't waste your breath on trying.

Using a Yahoo account, however, simply just don't work for me : which gives me an error message ’˜OpenID signature error' *shrugs*.

If you're interested to learn what identifier select, check out Directed Identity vs Identifier Select.

What OpenID provider are you using for Facebook linked account?