Apple did a minor tweak to the original iPad hardware, no! not adding a front-facing camera, but a Screen Rotation lock!
If you have noticed previously, the button was designed for muting the device, but Apple did a update on it and change it to a Screen Rotation Lock.
So what does it do? It actually lock the screen in the orientation that it is currently at when u click on it. Thus the screen will not change it orientation when you move while browsing the web or watching a video clip.
From my opinion, I think it is a very good idea, as most people will be using iPad as their main reading or browsing device. And most people will do the browsing or reading or watching on the most comfortable place – The Bed. With this orientation lock, users can lay on the bed, sit on the bed or any position they like and still be able to enjoy the iPad without worrying about the orientation changes.
Very good job Apple to understand use case by users!
Apple started their iPad Pre-Order, now users can purchase iPad and it will ship by April 3!