One of the Facebook engineers said the new application has been built primarily using Objective-C, the programming language used to build applications for iOS. Many of the components of the current version of the Facebook app are built using HTML5, a Web-based programming language.
The current version of the app is essentially an Objective-C shell with a Web browser inside. When it comes to speed, this is like putting the engine of a Smart Car in the body of a Ferrari.
I hear the new version is out there in the wild being tested right now. And as Bilton says, I hear it’s very quick.
To get a better sense of it, one might look to the Messenger and Camera apps that Facebook has put out there. Also notice that their icons are slightly different from the main Facebook app icon. Change is in the air.