As we all know, users can register/log into sites using their fb details. But what if you want to log a user into a separate web account within fb, such that the fb password and other web login passwords are different from each other? It is easy to log into that other web account from facebook using your username and password (external website is embedded into fb), but can you log a user automatically into the other website (with a different password)within fb? So basically integrating the external user database with the facebook database, and running a double authentication when logging into facebook(firstly the authentication for fb then the authentication for the external website login)
Note that the key difference here is that the fb login details and external website login details differ. Is this possible?
Hope I didn't articulate this too bad.
Thanks