In your day to day life you come across various devices, computer programs and games where you will have to make choices. It might be an icon to click, to steer left on a racing game or press of button on your iPod. In response to the action you make the program or device gives you an output. This is called Being Interactive.
Throughout the years, the computer programs and devices have increased its input capabilities. Multiple inputs have been introduced and programs with a higher rate of interactivity have grown with time. The traditional input devices like keyboard and mouse have turned into gesture recognition systems or facial recognition systems and voice recognition systems.
People tend to express themselves more with inputs like these and give you much more entertainment (Ex: Microsoft Kinect) and let you feel connected to the program itself. Different
technologies have been introduced to serve different inputs and purposes with evolution of technology.(Ex: To serve the differently able or Face recognition in security systems)