atmega16 in Arduino Board I had a very common question. Why a additional MEGA used in most of the Arduino Boards. Arduino board Mega2560 also have a MEGA16U2 controller on board which i think is used for programming via USB. Is there any other specific usage of atmega16 on arduino board. 

Thanks
It's an ATmegaU2, which has USB hardware and handles the USB communication. It passes the hex file on to the bootloader in the main microcontroller. That is its only job.