***PLEASE. ..PLEASE. keep your coins in your own wallet. First of all you get rewarded nicely with POS while helping secure the network. Secind this has happened too many times and it WILL happen again. Would you let some random unknown uninsured company keep your fiat money. If not this should be the same thing. Deposit trade then withdraw. Unless you day trade and then you are on your own.
Yes, we had this discussion here not so long ago, when someone asked why the online wallet had a disclaimer on it.
If Government servers can be hacked with all the money they have available to throw at security then realistically what hope do altcoin exchanges (or online wallets) have? Keep most of your coins in your own wallet (with multiple copies of your wallet.dat file securely stored and only keep on the exchange/ online wallet the absolute minimum of what you need.