Six Sigma...What ???

I carry one quote from Mr. Azim Premji (for who Eats business, dreams business and sleeps business). Quote " Successful leaders have made Six Sigma their way of conducting business" / Unquote.
I really agree to his flow of thoughts,But i guess its THE most underrated and least tapped way of executing business. You bet, it is a real volcano, gathering enough power, Gases etc (read proponents) to engulf whole IT world.
But thats future, i thought of coming up a Six Sigma series to give back/ share what i have learnt being a practising Green Belt.

Clarification : Six Sigma is way beyond 3.4 defects per million oppurtunities. It actually targets to return process efficiency of 99.99966%.
In other words process Standard deviation should be so low that it can fit into client performance limits without any hassel.Believe me it aims at such a process in which no matter what target deviation happens it still is within the customer demands. 6Sigma is actually a variance based thinking and where mean is meaningless.
It has three main advisors - USL - Upper Specification Limit (Anything above this is a defect), LSL -Lower Specification Limit( Anything below this is a Defect) and Target (Usually the middle point of USL and LSL).
Six Sigma super set contains - Metric, Culture, Way of Life,Locomotive, Benchmark and of course GOAL.