In June of last year, I demonstrated a proof of concept of using Facebook as an identity system for your blog. My proof of concept used the standard Facebook Application API as opposed to the Facebook Connect API (which didn’t exist back then).
The Facebook Application API is designed to be used for applications which live on apps.facebook.com. In my proof of concept, I redirected the user to apps.facebook.com which “set up” the session before redirecting back to the blog.
The Facebook Connect API provides a much better experience for the user as it’s designed for integration with external sites.
For WordPress users, you can use WP-FBConnect to integrate Facebook into your blog today. It will integrate the user system of Facebook (i.e. your identity), profile pictures and news feed publication of comments.
Literally hot of the press (it’s been available for less than a week), I strongly recommend testing the plugin on a local WordPress install before making it available on your public blog. See the Facebook wiki for more info and Q&A about the plugin.
It seems like a fantastic idea to me to be able to use a Facebook identity around the web. My concern though is that, so far, I’ve kept my Facebook identity within people I know in real life and I hesitate about opening up my Facebook identity to the public on all kinds of random blogs and forums. Only time will tell if Facebook Connect will work well and whether people will be happy with the privacy aspects of it.