So 大量放水 is ok when encomic is growing fast.
QE3是大量放水 because it makes the interest rate so low and it is buying those Agency bonds, it directly distort the market (like housing market). And directly fight the invisiable hand even the market is calm and reasonable.
QE1 and 2 is to calm the market and necessary. QE3 (endless QE) is not necessary, but it does have a good intention to bring back inflation. Let us watch the chain reaction, could be another bubble coming.