Unless you have lots of capital and balls of steel, I strongly recommend against shorting bitcoin.
Even if you don't short, the fact that dollars are worth more after tapering will lead people to not pay as much for a bitcoin. Dollars would purchase more of other assets. It's going to be problem regardless, but I think one of the large hedge funds dumped a lot of BTC yesterday. I saw an order for a 30,000 BTC sell yesterday. Right after the FOMC minutes came out... Co-incidence?
The USD is rising in value against many major western currencies such as the AUD and CAD and GBP...
You likely saw the gox API glitch caused by a 10k sell. The API repeated the information like a loop for quite sometime making it look like far more was being sold than actually was.