The MemberMouse Social Sign On Extensions will allow new members signing up under a free membership level to sign up and login to your site using their Facebook, Twitter, Google, or LinkedIn login credentials.
If a member already has created an account, they will not be able to retroactively associate that account with the social sign on option. In this case, the current account would have to be canceled and a new one created through Facebook, Twitter, Google+ or LinkedIn.
The social sign on can not be used in checkout pages to start paid memberships. In order to use this extension with paid memberships, the user has to first log in via the social sign on to a free membership, then gain access to checkout pages where they can make normal purchases.
Please note, if you are WP Engine hosting customer, read this article to learn about the issues you may have running SSO in a WP Engine hosted environment.