[note this post is under going revisions and will be updated]
Some tips on Adding FaceBook sign-on authorization – it takes a number of steps not all of which are well documented on http://rpxnow.com. This post assumes you’ve already installed the plug-in to your site (WordPress in my case) and have it working with the default installed 3rd-party providers (Google, etc…). I’d never created a Facebook App before so I had to allow the Developers App in my account. It then took a while figure out what an API key was and how to get one. After that then finish up the steps for adding Facebook as a sign-on provider back on the rpxnow page.