Quantitiative Easing- Struggling to Make Sense of it.

What exactly is the point of quantitative easing? Two weeks after the U.S. Federal Reserve decided to buy $600 billion of government bonds, the debate still rages. The U.K. has already purchased 30% of the existing stock of national debt, and the Monetary Policy Committee is clearly willing to countenance buying much more.
The question is what all this government bond-buying is supposed to achieve? The Chinese believe the U.S. is using QE to attempt an underhand devaluation of the dollar, a view apparently shared by former Fed chairman Alan Greenspan. Others believe the purpose of QE could and should be to provide liquidity to the banking system, both via the accumulation of cash deposits and the increased supply of funds to buy bank bonds. Given so many competing views, it's no wonder people are confused. Some economists have concluded the attitude of central banks to QE is to shoot first and declare whatever they hit is the target.
But that is hardly a recipe to instill confidence, perhaps the most important channel through which QE is likely to work. In fact, confusion over motives could even act to damage confidence if the markets start to question a central bank's commitment to fighting inflation and willingness to unwind QE. It is hard to feel confident about how QE will end if you don't know why it was begun.