Please note that I have taken the website offline. I am consulting legal council about the current situation and will post once I have more details. I want to make sure the matter is handled appropriately given the financial situation the exchange is currently in.
The website was causing too much confusion in the current form and once I have more details I will post a very clear message for all users.
This is the best option for you. Given the size of the loss (assuming the courts system would hold up a value for the BTC lost if action was taken against you), you're looking at a huge risk if you handle things inappropriately and any one of your users files any sort of legal action against you. We appreciate the notice, but you need to cover your butt, especially if you're in the US. At current exchange rate, a loss of a quarter million U.S. dollars worth of a commodity is gigantic and definitely warrants legal council on how to proceed.
You seem like a nice guy and I really appreciated the service when it was running before all this. Assuming you're not the perpetrator (something that a few members might suggest in speculation), I wish you the best and hope things can be resolved. Your personally liability for this may be incredible compared to any sort of profit you may have realized for providing the service. Looking out for your personal future (not even the future of BitFloor), I would seek immediate legal council.
Sadly, if you seek GOOD legal council... Their first piece of advice would probably to take the site down with a notice and keep as quiet as possible until everything is figured out.
Best of luck.