It's interesting to see just how dramatically and quickly these moves can happen.  It really does seem like all it takes is a few whales to take some significant profits, and then it immediately becomes falling dominos, people who were quite comfortable just holding and letting it ride suddenly start thinking, "This could come down a few thousand, it's time to lock in some large profits and let it come down and buy back in later".  And of course, multiply that mentality by several hundred thousand people and you have a "flash crash", a self-fulfilling prophecy.  How fast one can get in and get out becomes an important consideration.  I'm not a trader so I'll just wait and if it does come down a LOT I'll will be very excited to buy more.