Yesterday Mark Zuckerberg didn’t shock the world. Instead he announced the long-awaited “Facebook phone,” which, it turns out, is not a phone at all. Instead it’s an interface for specific Android phones that makes using Facebook a top priority. It’s built on top of Android, so it’s not an operating system, but it is a more thorough experience than an app, or even some of the other proprietary “skins” we’ve seen from manufacturers like HTC in the past.

So what does the Facebook Home experience feel like? Well basically, it puts Facebook front and center for your mobile experience. Both your homescreen and lockscreen will display updates from Facebook (the feature is called Coverfeed), so you don’t even have to really be using your phone to be interacting with your friends and family.

Once you’re actually using the phone there’s deep integration with Facebook chat – on the phone it has the name “Chatheads” – that lets you see a person’s face and tap to message. It’s an attempt to streamline how we message and replace SMS with Facebook’s own utility.

And of course there are notifications. Lots of them. But it’s different from the way we use our phone now, where an app will send push notifications when something happens. Instead, you’ll get alerts that friends have done something. It’s a people-centric design, which makes sense in that Facebook is best used as a connector of individuals.

Right now the HTC First, available exclusively from AT&T, is the only phone coming pre-loaded with Facebook Home. It’s available for $99 with a two year contract, and will come in red, white, black and pale blue. It comes with a 4.3″ screen, 5 megapixel camera and 1.6 megapixel rear camera.

Go to AT&T’s website for more info.

What do you think? Would you make Facebook your top mobile priority?