There has been chaos among the users of Binance exchange as the trading and withdrawals are suspended by the exchange. They stated that "due to increasing number of users and trading volume, their system needs to upgrade", they also denied of being hacked. If they have already planned this maintenance work, then why they did not informed the users in advance ? 10-12 hours outage is too much and prior notification was required. Binance is one of largest exchange and such poor service is not expected from them. They also need to upgrade their technical team to avoid such incidents in future.
http://bitcoinist.com/crypto-exchange-binance-goes-dark-12-hour-outage-maintenance-system-upgrades/I have few alt-coins on binance, i hope everything is fine and nothing has been lost.
A hack is a real possibility that cannot be discounted here.
I believe that for whatever reason, if any exchange wants to put a halt to trading activities then it should at least have its users notified 1 day before the scheduled maintenance happens. If they don't, not only will it mean that users are grumpy because of inability to access their funds, it also means that unnecessary speculation will come out.
And seeing that Binance usually is quite good at customer support and communication compared to other exchanges, I'm surprised at this. Since they've denied it, the chances are that they're probably not hacked, but as i said, always a possibility in these scenarios and obviously exchanges want to cover it up if it does happen.