biotech
My advice: go through the arduino samples. You are lacking quite some basic knowledge. Going through the samples will help you understand what is going on in this world.
Zoomcat
The adafruit motorshield only makes it easy to connect a servo. Basically the 2 times 3 pins (+ gnd pwm) are put nicely next to each other so you can plug in 2 servo's using the standard servo connector. it is a "extra feature" of the motorshield which is very often misunderstood as a real feature of the shield.
If you have the shield lying around and need to work with servo's it is convenient.
Best regards
Jantje