Hallo, can you please answer:

1. How can I determine if a user was logged in by Facebook?

2. If a user was logged in by Facebook, later how another user can log in differently (not by Facebook) from the same machine (without removing the cookie)?

Thanks

As I see the username is taken from users Facebook e-mail (first part), and how this can be used to determine whether a user  logged in via Facebook?

 Actually  I found the way:

DotNetNuke.Services.Authentication.AuthenticationInfo authenticationInfo = DotNetNuke.Services.Authentication.AuthenticationController.GetAuthenticationType();

if (authenticationInfo.AuthenticationType.Equals("Facebook"))
{
  //...
}

But there is still the second question...