possibility case :
price btc go down because silkroad get hacked.
and the hacker using mtgox to cash out the money. lol
btc price is about the demand.
i can tell 40% ppl using bitcoin to buy drugs,etc on silkroad.
50% is miner
10% trader
without silkroad btc is nothing.
silkroad is most certaintly a good portion of bitcoins use i agree with this statement