This happened today...
Today we discovered a security breach that requires us to halt all trading on Bitfinex, as well as halt all digital token deposits to and withdrawals from Bitfinex.
We are investigating the breach to determine what happened, but we know that some of our users have had their bitcoins stolen. We are undertaking a review to determine which users have been affected by the breach. While we conduct this initial investigation and secure our environment, bitfinex.com will be taken down and the maintenance page will be left up.
The theft is being reported to — and we are co-operating with — law enforcement.
With the DAO Hack and recently, Steemit hack,
We should actually start discussing and looking into security in a more serious way to avoid any problem with STEEM
EDIT : Looks like i'm 1 hour late ;)