John "Grumpy Economist" Cochrane elaborates.
It's more about opportunities for future research than about policy implications.
To be clear, both my post and Gerard's are not really critical of the Fed. If "pyrotechnics'' helped, good. If QE is not "mechanically" that powerful, great, we all learn from experience. A large interest-paying balance sheet and silence is probably the best thing for the Fed to do right now. This question is most important to academic and historical analysis, to learn what causal mechanisms really did play out, and what will work in the future.