A year ago Woo Bull predicted that soon the volatility of BTC will match those of central-bank-issued currencies: http://woobull.com/bitcoin-volatility-will-match-major-fiat-currencies-by-2019/
Of course, his (and Vinny Lingham's) target prices have turned out to be massively wrong, but the central point still stands.
Penny stocks are much more volatile. What is happening to Bitcoin is 100% normal when you compare it to new, small companies. Once a company like that makes an announcement that they're reaching a breakthrough their shares go up and when the competition spreads FUD they go down.
I'm sure it will decrease with time. We can already see it starting to decrease with dips getting much shallower.