Newbie Questions about how JFB works with Joomla registration

If a new user logs in to my Joomla site using the user's FB credential via JFB, is the log in just for that one visit OR is the user automatically registered to my site?

JFBConnect creates 100% standard Joomla users. Once registered/created on your site, they could login using Facebook or a set of Joomla credentials that are created for them. Extensions on your site will treat them just like any other Joomla user.

If the same user as in the first scenario decides to register to my site as a Joomla user subsequent to the prior log in via that user's FB credential, and assuming the user registers using the same email address as used in FB, will JFB connect automatically recognize that it's the same user (assuming FB email address is saved from the first scenario?

If the user registers through JFBConnect, they already have a Joomla account and shouldn't need to register again. Conversely, if a user already has a Joomla account, you can configure JFBConnect to automatically connect an existing Joomla user to their Facebook (or Google or LinkedIn) account if the email on the accounts is the same.

If JFB recognizes the user from the prior FB login, is the user information such as name, image, etc (as stored in the users table) based on the FB information (from the prior FB log in) OR based on the Joomla user profile? Which one will override the other, if at all?

The user's basic information (username, name) is stored in the standard #__users (Joomla users) table. Extended information, like avatar, address, interests, gender, etc, can be stored in 3rd party extensions like JomSocial, Community Builder, K2, Kunena and others.

I understand that JFB automatically creates Joomla details for the FB user, which login method (FB or Joomla) is the prefer log in the next time the user logs in?

Whatever the user prefers On this site, I regularly finding myself randomly logging in with my Joomla, Facebook, Google, Twitter or LinkedIn credentials. It depends on what service I know I'm currently logged into.

If this user logs into my site as a Joomla user, then the user independently logs into FB, will JFB automatically picks up the user FB information (e.g., friends, name, profile, etc) because both accounts are logged in at the same time?

See above as I sort of answered this for existing Joomla users. Our SCLogin module can also present the networks the user hasn't already connected to their accounts. For instance, hover over the My Account menu in the top right. You should see whatever social networks you *haven't* already connected to your account. Click one of them and it will authenticate and make the association between your current account and that social network user.

With that said, it's not perfect as users can still create distinct accounts under some circumstances. If they register in joomla with email This email address is being protected from spambots. You need JavaScript enabled to view it. but then register with Facebook with This email address is being protected from spambots. You need JavaScript enabled to view it., if you have automatic account creation enabled, it will create a new account for the This email address is being protected from spambots. You need JavaScript enabled to view it. account. When automatic registration is off, the user will be presented an option to login with an existing Joomla account or create a new one. Also, as above, the SCLogin module can offer the user an option to connect accounts. So, it happens, but can be controlled so it's not frequent.

I hope that helps explain, but if you have other questions, just let me know,
Alex