What is Spine Aligning (The Short)

Best and easiest way to Explain Spining?
Finding the natural and least point of resistance of the golf shaft.
By Spining your shaft the club face will open and close when you
want it to not when the shaft wants it to.
Most Golf Shafts have a Flaw of some Kind. 
#1 Not perfectly Round
#2 Weighting Problem
#3 Imperfect Shaft Materials
We find the Spine of the shaft and place it into the head, we then
place the Spine Towards or Away from the target. This way we are
ISOLATING the Spine so it is no longer a factor in the flex of the shaft.
You now have two positive areas of the Golf Shaft.

All golfers put a bending force on the shaft at some point during the downswing. If the spine effect is moderate to severe in the shaft, when the shaft bends in response to the golfer's swing force, the direction of bending of the shaft can move off the direction of bending, thus shifting the position of the club and clubface. This can then cause the golfer to hit the ball more off-center than their swing might have otherwise ordained.

We would also like to clear up a few myths on spine alignment,
first the USGA only allows a spine to be oriented or aligned in a
neutral position (facing towards or away from the target).
Second there is no real solid proof that a shaft can be oriented to
aid in the drawing or fading of the ball, I truly believe in spine matching
as an effective means for the shaft to be more consistent, but for
someone to claim that they can align the shaft to aid in
fading or drawing the ball is "smoke and mirrors".

* Note Graphite Shafts have Graphics or Logos That may not line up Perfectly Once the Club is Spine Aligned

The Physics of Spine Aligning (The Scientific Explanation)
Spine orientation, or spine aligning, the new process which measures
a shaft under both constant and dynamic load to precisely locate the
shaft's inconsistencies in shaft wall thickness,shaft straightness,
shaft roundness and shaft material.

When a shaft's most predominant spine is properly aligned in a neutral position,
the shaft bends along the Principle Planar Oscillation Plane, the longitudinal plane of bending through which a shaft can move as closely as possible to a perfect straight line with no movement in any other direction. Thus, the shaft unloads or kicks forward during the golf swing. By decreasing the shaft's movement in directions other than the final swing plane, we, as clubmakers, can reduce shaft-induced mis-hits and stabilize torsional stiffness for more distance, accuracy and better feel.
In fact, some industry experts believe that spine matching is even more important than frequency matching. 

More Information on Spine Align

In February 1999 the USGA Implements and Ball Committee
modified its rule on golf shafts which required that they
"bend symmetrically in all directions". The reason for the change
is that it was proven to them that today's technology would not
support manufacturing of a shaft with these "symmetrical properties"
without raising prices to unrealistic levels. The USGA concluded that
it would "not be against the rule" for club (and shaft) manufacturers to
"orient the shaft in the clubhead such that the shaft appeared to bend
symmetrically in all directions".
 

Quotes on Shaft Spining from Industry Experts

- By properly orienting the shaft in a clubhead, the maximum performance
of the golf club can be obtained.

- New tests show promising evidence that spine orientation has a positive impact on a golfer's distance and accuracy.

- Our research is showing that haphazard spine placement in clubs within a set
can be the primary reason why golfers often have both favorite and least favorite clubs.

- Results were phenomenal - the test golfers experienced between 20 percent and 60 percent improvement in their percentage of on-center hits after spine orientation.

This Information is Copyrighted by Custom Golf Sales, Inc.
Other Than the Direct Quotes Taken from Industry Experts