This is different from what the Fed normally does to stimulate the economy. Normally it prints money to buy short-term bonds. But, since short-term interest rates are already near zero, the Fed has to take the riskier action of buying longer-term bonds if it wants to stimulate the economy.
Harvard economics professor Martin Feldstein, President Emeritus of the National Bureau of Economic Research, warns that this is dangerous and may blow new bubbles:
The Federal Reserve’s proposed policy of quantitative easing is a dangerous gamble with only a small potential upside benefit and substantial risks of creating asset bubbles that could destabilise the global economy. Although the US economy is weak and the outlook uncertain, QE is not the right remedy.It sounds to me like Feldstein is saying The Onion was right.
Under the label of QE, the Fed will buy long-term government bonds, perhaps one trillion dollars or more, adding an equal amount of cash to the economy and to banks’ excess reserves. Expectation of this has lowered long-term interest rates, depressed the dollar’s international value, bid up the price of commodities and farm land and raised share prices.
Like all bubbles, these exaggerated increases can rapidly reverse when interest rates return to normal levels. The greatest danger will then be to leveraged investors, including individuals who bought these assets with borrowed money and banks that hold long-term securities. These risks should be clear after the recent crisis driven by the bursting of asset price bubbles. Although the specific asset prices that are now rising are different from last time, the possibility of damaging declines when bubbles burst is worryingly similar. ...
The truth is there is little more that the Fed can do to raise economic activity. What is required is action by the president and Congress...
As for other notable economists' thoughts on the Fed's actions, John Taylor is opposed and Paul Krugman is ambivalent.