Samsung Galaxy S III was the first to debut "Smart Stay". With this feature, the front facing camera makes sure that you are still looking at the screen so that it doesn't turn off and go to sleep while you are in the middle of reading something.
Out of the box, "Smart Rotation" is off by default. But all you need to do is go to Settings> Display and turn it on. And remember, these are not Google-devised features for Android but are proprietary to Samsung devices. What "Smart" thing will the Korean manufacturer come up with next?
Just the other day, we showed you the multiwindow feature on the Samsung GALAXY Note II along with other features that Samsung included on a video about the device. Strangely enough, some units of the model are not being shipped with multiwindow capabilities.