Earlier quoted context omitted.
OK, let's play a game. Say you had $5mm. How would you manipulate the Bitcoin market and earn a guaranteed return?
A government entity looking to destroy the market wouldn't necessarily care about getting a return. Even if they were, take a look at what happened yesterday when someone dumped 5k bitcoins onto mtgox. http://i.imgur.com/K8T4F0Y.png
My personal (amateur) theory is that people were hovering over their "sell" buttons, looking to cash out as we approach the landmark $100 point. Once they thought someone with a lot of coins was bailing, they took that as a sign to head for the exit.
I also think that MtGox's horrible lag factors into the dips. Their trading engine was running as much as 8 minutes behind during this event, which causes people to not be able to modify or place orders. Along with not being able to see actual "current" trading info, this causes a certain segment of the trading population to go into full panic mode.
Placing market sell orders in an engine that's showing you ancient data during a crash seems suicidal, but for some reason people do it.
I'd love to see Gox upgrade its engine. I honestly think it would make a notable difference in price stability.
Even better, I'd like to see the market grow strong enough to support 3 or 4 primary trading sites. There are a number of others now, but the rest have such low volume that you should only use them to pursue specific opportunities (arbitrage).