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.
Edit : Subject updated.