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.