China moves down a bit, gox follows. Stamp's orderbook bids a bit thin.
btw, why don't they just close the exchanges on the weekends like the stock market?
Simple, really... there are a bunch of competing exchanges with a global client base. If you shut down your exchange, even for a few hours a day, you're losing customers to your competition.
So no exchange will ever be the first to limit their hours of operation, and therefore the other exchanges will never limit their hours either.
Prisoner's dilemma.