Columbia professor Jeffrey Sachs is someone I rarely agree with, but he may have a point here in this Financial Times article:
the zero interest rate policy has a risk not acknowledged by the Fed: the creation of another bubble. The Fed has failed to appreciate that the 2008 bubble was partly caused by its own easy liquidity policies in the preceding six years. Friedrich Hayek was prescient: a surge of excessive liquidity can misdirect investments that lead to boom followed by bust.
Link via the Taking Hayek Seriously Twitter feed.