Today the FOMC announced that it would taper (i.e., reduce) its purchases of Treasuries and MBS by a mere $10 billion beginning next month, and that it would likely take more such baby steps in the future, at a pace consistent with continued improvement in the economy.
$10 billion is such a small fraction (about 6 bps, or 0.06%) of the Treasury and MBS market as to be insignificant. It's the equivalent of easing up on the gas peddle by several microns. The only real impact of today's decision is that it puts the Fed on track—finally—to eventually reverse its Quantitative Easing purchases which began some five years ago, though the beginning of an actual reversal is unlikely to occur for many months. Better to make this decision sooner rather than later, especially given the ongoing improvement in the economy.
Today's timid tapering announcement represents no threat whatsoever to the economy's ability to grow. It would have been worse if the Fed had refrained from tapering, since that might have allowed future Fed chair Yellen to succumb to her dovish instincts and postpone the decision needlessly.