I just noticed this article by the FT's Sam Fleming, in which he writes that Boston Fed President Eric Rosengren has pointed out the potential benefits of raising the US inflation target. The implication being - as Blanchard, Krugman and others have pointed out - that we now know booms and busts are big enough that the old one can send rates to the zero bound. And aside from that, we suspect that the equilibrium real rate - also crucial in determining how far above zero the central bank rate lives - will be lower than before for the foreseeable future.