You can shoot pictures that have less camera shake by increasing the shutter speed. Conversely, you can purposely add blurring to pictures by reducing the shutter speed.
(More camera shake) 1/8|1/10|1/13|1/15|...|1/3200|1/4000|1/5000|1/6400
|1/8000|1/10000|1/12800|1/16000|1/20000|1/25000 (Less camera shake)