There would still be some people that would think "Well I'll just enter my Facebook credentials to verify my Facebook Card". The problem the site creates is the login form that has a username input, password input, and a "Connect with Facebook" button. The user interpreted it as "If I type in my FB credentials and click this FB button, then FB logs me in."
Instead, they should start with making the user pick "1) Log in using a Buyosphere account, or 2) Log in using Facebook Connect". It's much less user friendly, yes, but that's the consequence of having multiple authentication systems.
Instead, they should start with making the user pick "1) Log in using a Buyosphere account, or 2) Log in using Facebook Connect". It's much less user friendly, yes, but that's the consequence of having multiple authentication systems.