Facebook's mobile platform has three parts, single sign on, location API and deals. And they're focusing on doing software instead of making a phone.
Now you can use one login for all your mobile sites, meaning, log into Facebook, and then Facebook will handle your "logging in" to other sites through their APIs. There's also deals, which takes advantage of your Facebook single sign on for authentication, as well as location APIs. So what's that mean? You can see where you friends are, write and publish checkins, and search for relevant places. Mostly only cool for developers, but, it allows apps to do more things. [Facebook Deals]