Anyone that uses the Facebook app on the iPhone knows that it is very slow. The pictures load slow and scrolling up and down is slow. The navigation is slow too. On the Apple App Store, the Facebook app has 38,000 reviews and 21,000 are 1-star out of 5. People describe the app as being slow. According to two Facebook engineer sources with the New York Times, Facebook has completely rebuilt their iOS application to be optimized for speed.
The new app has been built using Objective-C. A lot of the code in the current version of the app was built using the web-based markup language HTML5. The current version of the app is an Objective-C shell with a web browser inside. HTML5 uses the speed of the Internet to pull in the user interface and content whereas Objective-C takes advantage of the hardware in the device.
The new Facebook app should be out by this summer. The new app will look exactly like the current one. The reason why Facebook built the app in HTML5 because it reduce the amount of work for Facebook mobile developers. They would be able to reprogram the app easier for multiple platforms, unfortunately at the cost of the users.