Thank you, Dad. I can see patterns in Mt. Gox charts but can not short nor set stops on Mt. Gox. I would like to understand Bitcoinica's behavior. Is it executing my BUY-STOP when the BID is greater than my BUY-STOP, or the BID/ASK mean, or what?
$3.05 STOP for a Mt. Gox $3 and $0.1 Bitcoinica spread were useful answers, but I'd prefer it confirmed by Zhou.
No need to be a jerk. The nature of your questions suggest you have a weak understanding of FOREX, and so I was giving you a response appropriate to your understanding. This is not an insult, it's a pretty complicated system.
I can't tell you exactly HOW the spread is calculated (and Z won't), and I can tell you that your stops and standing orders are executed based on Bitcoinica's Bid/Ask, which could be wildly different than anything you're seeing on Mt. Gox, in theory. The only relationships the sites share are 1) Bitcoinica trades on Mt. Gox, and 2) Bitcoinica's users trade at Mt. Gox.
Because of those and arbitrage, you'll almost always see Bitcoinica's spread surround the current Mt. Gox price. But Mt. Gox's price is
completely irrelevant to any of your profit and loss transactions on Bitcoinica, and the fact that you keep on it is, again, an indication that you're confused.
If your orders are not executing at exactly the Bid/Ask prices, it's due to something called "slippage":
http://winninginvestor.quickanddirtytips.com/liquidity-slippage-selecting-stocks.aspxI hope that helps, son.