What is Quantitative Easing?

If you listen to economists, a term they sometimes use is "quantitative easing." For most of us, we haven't got a clue what that means and as a result we really haven't got a clue about what that economist has just said.

What is Quantitative Easing?
The term quantitative easing describes an extreme form of monetary policy used to stimulate an economy where interest rates are either at, or close to, zero. Normally, a central bank stimulates the economy indirectly by lowering interest rates but when it cannot lower them any further it can attempt to seed the financial system with new money through quantitative easing. [From Wikipedia, the free encyclopedia]

Quantitative easing is seen as a risky strategy that could trigger higher inflation than desired or even hyperinflation if it is improperly used and too much money is created.