The difference between Cloud and Grid computing is probably not important to the average small business or consumer. Its only when there is an enterprise requirement for on-demand scalability that a grid system may provide a solution. Fortunately many hosting companies already have a grid solution as a part of their infrastructure. Options like Computer Associates (CA) Applogic from scalematrix.com provide similar functionality.
Why Cloud Computing Is Better Than Grid Computing | CloudTweaks.com - Cloud Computing Community