"Since yesterday, we are continuing to experience a DDoS attack like we have never seen," the company said in a statement on its Web site. "While we are being protected by companies like Prolexic, the sheer volume of this DDoS left us scrambling to fine-tune the system every few hours to make sure that things don’t go beyond a few 502 error pages and trading lag."
The company suggested that the attack may be aimed at destabilizing Bitcoin in general, and at abusing the system for profit. "Attackers wait until the price of Bitcoins reaches a certain value, sell, destabilize the exchange, wait for everybody to panic-sell their Bitcoins, wait for the price to drop to a certain amount, then stop the attack and start buying as much as they can," the company stated. "Repeat this two or three times like we saw over the past few days and they profit."
At bitcointalk.org, one commenter agreed, writing, "The one a while back I got [lucky] and sold pretty high, and bought at bottom... I didn't do the attack... just noticed it dip Friday night and sold... bought when it started rising again."