One of Bitcoin's biggest strengths is that they cannot be shorted - you have to have Bitcoins to sell them - so we will not see the extreme volatility you see in other places.
The bitcoin cannot be shorted today as there is no easy and fast procedure to do that,
to do a short means to borrow, if there is an active market you can always borrow from it... you just need the securities.
When the bitcoin will grow a bit more I'm sure it will be easier to take a short position.
(being able to do a short position is actually a good thing - It improves liquidity and helps to find the fair value)