Anh,
Thanks for the link. They do have the OpenID library open, but we're really hoping for an OAuth library at some point. OpenID is pretty old technology and no virtually no providers use it anymore. JFBConnect natively supports OAuth1 and OAuth2, but could pretty easily support OpenID as well.
The big problems with Steam's implementation though is that there is *no* profile data available. If a user logs in using it, you wouldn't be able to get their email address, name or any other profile information. There's some basic game stats that you can get, but it's not something that's similar to other profile fields that we currently import.
In general, it seems pretty limited and not similar to a lot of the features we currently have. It is on radar and likely will be implemented at some point next year, but it's not a high priority for us due to the limitations above.
I hope that helps,
Alex