Can anyone explain the difference between WiringPi and the default RPi.GPIO module that comes with raspbian?
What extra features does WiringPi have?
wiringPi is a C library. Bindings have been provided for other languages like Python and Java. As mentioned above wiringPi comes with a command line utility called gpio which is setuid root so the gpio utility can be run by a non-root user.
RPi.GPIO is a Python module.
Programs linked against wiringPi have to be run as root as does any Python program which imports RPi.GPIO.
If you look at the web-sites you can make a feature comparison. Generally wiringPi has a lot more features available, SPI/I2C, Gert board ec.
WiringPi has a command line utility called 'gpio'. This makes it possible to control GPIO pins from the command line. Read about it here: http://wiringpi.com/the-gpio-utility/
WiringPi doesn't need to be run as root, but programs built with the RPi.GPIO module do need to be run as root.