Haptic feedback is a system that gives mobile terminals the ability to "respond" when a user interacts with them. In general, this feedback refers to the vibrations you feel when you use a gamepad and play a game that has the technology implemented, and Apple wants to bring it to its terminals. Company develop a linear haptic feedback system that would allow providing feedback only in certain portions of the screen of a mobile terminal. More precisely, when we press a certain portion of a screen, it will emit a vibration only in that location, and we will know that we have pressed a suitable button, for example.
Furthermore, the vibrator may be configured to be activated when a user touches a particular portion of a touch-sensitive screen of the mobile phone. When the user's touch or near-touch is sensed in the appropriate area of the screen, the vibrator may be activated in a boosted mode, thereby providing localized haptic feedback directly under the area in which the touch was sensed. In this manner, the localized haptic feedback may serve to confirm the touch to the user, for example by emulating the feeling of pressing a button.
Such systems are extremely interesting and highly appreciated by users, but they also consume quite a lot of energy. It was speculated that iPad 3 will come with a very interesting haptic feedback system, but in the end this did not happen, but there are hopes for future mobile terminals. Think of it as if the keyboard buttons in iOS vibrate when you touch them, or the camera button emits a short vibration when you record a picture, the same thing being possible even inside games or any other applications. Of course, no one knows if this system will ever reach iDevices, but it seems very interesting.