Yes Im using Jomsocial, registration component in JFB connect is set to "JFBConnect"
I have set "Skip Joomla activation" to "YES" and try all user activations parameters:
If user activation set to "No activation" ("Aucune" in french) ---> user get no mail confirmation and when they try to log: "Failed to authenticate: Access Denied" (user not active and not actived in administration")
If user activation set to "Auto-activation"---> user get a mail without activation mail (but with username and password) and when they try to log:"Failed to authenticate: Access Denied" (user not active and not actived in administration")
If user activation set to Administrator --> user get a mail with 2 DIFFERENTS ACTIVATIONS LINKS and when they try to login: "Login denied! Your account has either been blocked or you have not activated it yet." (user actived but not active in user administration)
If you want to try :
www.webmaster-seotools.com
----EDIT: User registering with Facebook can login
(Again sorry for my english, I use french language in administration so some words can change...)