[exelius]

The #1 mandate of the federal reserve is to keep inflation steady at around 3%. They've done a pretty good job of this (with the exception of the 1970s). But QE isn't about causing inflation; it's about stopping deflation. QE is designed to stave off deflation by intentionally expanding the money supply.

Basically, the money supply was artificially inflated by the housing bubble. Once the bubble burst, a lot of money disappeared over the course of 3 months or so. So the fed is using QE to prop up the money supply so the dollar doesn't rapidly appreciate in value. What we've learned from Japan's "lost decade" is that deflation can have even more harmful long-term consequences to an economy than inflation (suddenly it becomes MUCH more expensive to make goods in the US than the rest of the world, banks stop lending completely because money gains value with no risk, etc.) It starts a chain-reaction cycle that is really tough to break out of.

So the fed wasn't gutting the value of the dollar as much as they were preventing it from appreciating value quickly. As good of a thing as it sounds like it is, it's a bad idea to have money become more valuable just by holding on to it. Inflation creates an incentive to invest your money back into the economy, and while rampant inflation is almost always bad, a small amount of predictable inflation is a good thing if kept in check.