What to do when a user logs out of Facebook but is still logged-in on my site

I have a website which users can sign up to using Facebook Connect (with the new OAuth 2.0 stuff). Now when a user logs out of Facebook they remain logged-in on my site.

I'm not using the JavaScript SDK as I don't like the "magic behind the curtains". So what should I do when a user logs out of Facebook? Should I care at all? I get the feeling I should try to catch this somehow and开发者_运维知识库 log them out of my site as well.

I'm using Django with a custom authentication backend for this.

Don't do anything. You are using facebook as means of authentication. The fact that the user logged out of facebook means nothing for that matter - He's stil the same user.

Do the users think of your site as a part of facebook? I guess not (assuming its not a facebook app, just a login via facebook). Then it would be surprising and counterintuitive from the user's perspective to find he's also logged out of your site when he only logged out of facebook.