Ben Bernanke Goes Hardcore Dove

That in itself was a surprise to the economy, as stocks immediately shot up.

In his press conference, Bernanke has gone even further down the dovish path in explaining the central bank's decision.

"As today's decision underscores, asset purchases are not on a preset course," Bernanke said.

That kind of language gives the Fed more wiggle room in terms of monetary policy.

Originally, the Fed wanted to see 7% unemployment before adjusting its third round of quantitative easing. Now, that guideline has been scrapped, allowing for more potential accommodation in the future.

In fact, the FOMC may not even decide to raise the federal funds rate - currently at the zero lower bound - until the unemployment rate is "considerably below" the 6.5% threshold.

And the chairman made sure to stress it was a "threshold," not a trigger. It may seem like an inconsequential difference, but not in central banking.

The FOMC, Bernanke said, took into account upcoming fiscal headwinds. Specifically, the government's upcoming (and routine) battle over whether to raise debt ceiling has the chance to rile markets.