#fufacebook

Today's launch of Facebook Usernames provides an obvious and exciting opportunity for Facebook to become an OpenID provider. Facebook have clearly demonstrated their interest in becoming the key online identity for their users, and the new usernames feature is their acknowledgement that URL-based identities are an important component of that, no doubt driven in part by Twitter making usernames trendy again.

It's interesting to consider Facebook's history with regards to OpenID and single sign on in general. When I started publicly advocating for OpenID back in 2007, my primary worry was that someone would solve the SSO problem in a proprietary way, irreparably damaging the decentralised nature of the Web - just as Microsoft had attempted a few years earlier with Passport.

When Facebook Connect was announced a year ago it seemed like my worst fears had become realised. Facebook Connect's user experience was a huge improvement over OpenID - with only one provider, the sign in UI could be reduced to a single button. Their use of a popup window for the sign in flow was inspired - various usability studies have since shown that users are much more likely to complete a SSO flow if they can see the site they are signing in to in a background window.

Thankfully, Facebook seem to understand that the industry isn't willing to accept a single SSO provider, no matter how smooth their implementation. Mark Zuckerberg made reassuring noises about OpenID support at both FOWA 2008 and SxSW 2009, but things really stepped up earlier this year when Facebook joined the OpenID Foundation Board (accompanied by a substantial financial donation). Facebook's board representative, Luke Shepherd, is an excellent addition and brings a refreshingly user-centric approach to OpenID. Luke was previously responsible for much of the work on Facebook Connect and has been advocating OpenID inside Facebook for a long time.

Facebook may not have committed to becoming a provider yet (at least not in public), but their decision to become a consumer first is another interesting data point. They may be trying to avoid the common criticism thrown at companies who provide but don't consume - if they're not willing to eat their own dog food, why should anyone else?

At any rate, their consumer implementation is fascinating. It's live right now, even though there's no OpenID login box anywhere to be seen on the site. Instead, Facebook take advantage of the little known checkid_immediate mode. Once you've associated your OpenID with your Facebook account (using the "Linked Accounts" section of the settings pane) Facebook sets a cookie remembering your OpenID provider, which persists even after you log out of Facebook. When you later visit the Facebook homepage, a checkid_immediate request is silently sent to your provider, logging you in automatically if you are already authenticated there.

While it's great to see innovation with OpenID at such a large scale, I'm not at all convinced that they've got this right. The feature is virtually invisible to users (it took me a bunch of research to figure out how to use it) and not at all intuitive - if I've logged out of Facebook, how come visiting the home page logs me straight back in again? I guess this is why Luke is keen on exploring single sign out with OpenID. It sounds like the current OpenID consumer support is principally intended as a developer preview, and I'm looking forward to seeing how they change it based on ongoing user research.

As OpenID provider implementation is an obvious next step that can't be that far off - I wouldn't be surprised to hear an announcement within a month or two.

HTTP redirect codes

As an aside, I decided to check that Facebook were using the correct 3xx HTTP status code to redirect from my old profile page to my new one. I was horrified to discover that they are using a 200 code, followed by a chunk of JavaScript to implement the redirect! The situation for logged out users is better but still fundamentally flawed: if you enable your public search listing (using an option tucked away on www.facebook.com/privacy/?view=search) and curl -i your old profile URL you get a 302 Found, when the correct status code is clearly a 301 Moved Permanently.

no.