ValueChain is the concept first put forward by M Porter in his book called "Competitive Advantage", a few years after his best selling CompetitiveStrategy book.

From MeatBall (click on link below for more)
* The ValueChain is the chain of steps and processes a business takes to create economic value between its suppliers and its customers.

A link from WikiPedia points to this location that has more explanation. See http://www.themanager.org/Models/ValueChain.htm which talked about different types of ValueChain

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CategoryProcessPrinciple