How do the value chain and value web models help businesses identify opportunities for strategic information system applications?

1.    Define and describe the value chain model.
2.    Explain how the value chain model can be used to identify opportunities for information systems.
3.    Define the value web and show how it is related to the value chain.
4.    Explain how the value web helps businesses identify opportunities for strategic information systems.
5.    Describe how the Internet has changed competitive forces and competitive advantage.