The position of our head is of the utmost importance for just about everything. From how we move in life, how we see things, how our neck feels, the health of the nerves in our neck and face and so much more. We use this position frequently in many of our asanas. Practice this at home with a mirror especially after being on a computer.
Yoga Journal explains this perfectly:
A neutral head is rooted firmly like a tree, in the "ground" of the upper back. When this head is seen from the side, the ear is aligned with the center of the shoulder joint, so that the head sits lightly on the top of the spine. Consequently (in the upright position), the back of the neck is long and gracefully arched in a natural cervical curve, the underside of the chin is parallel to the floor and the shoulders "hang" from the base of the skull. The chest and lungs are full and the heart is open. pg 83 Yoga Journal Aug. 2003