I wanted to add that naturally it is very costly to run this sort of attack. Because as you are artificially manipulating the prices, you have to keep paying ou

I wanted to add that naturally it is very costly to run this sort of attack. Because as you are artificially manipulating the prices, you have to keep paying out the customers' arbitrage profits. This is why willy caused MtGox to lose tens of millions of dollars in the end. Mark Karpeles was simply clueless or naive in thinking willy would help him. So don't do it, or you will lose money :) In summary, I do believe regulation can and already does help BTC. They bring finance professionals in the market who have a clue (unlike Karpeles). They bring trust. They bring more trading volume. These are all things that make BTC less manipulable, hence less manipulated.