I think the issue we all keep ignoring is the broken trade matching systems these exchanges use. There have been posts from people on btc-e and bitstamp who did not have their limit orders executed even with the price moving through them. The same thing has happened on gox in the past, thats why we see big sells plow down through the order book and the price instantly recovers because of all the missed orders and orders placed during the execution of the large sell. These trade matching systems are broken and need to be rewritten or replaced with real off real off the shelf systems. We get lag in an exchange because of this as well, each transaction appears to be handled on an exclusive or semi-exclusive basis. Momentum locks up the db, limit orders do not get fully filled, traders can not react, market makeing bots can not update their orders, and we get a mini flash/lag crash. We need exchanges that operate like real financial market exchanges, written by people with experience in them or at least learning from their mistakes.