I and others have been warning about Poloniex for a while now. The shutting of the Trollbox, the legions of complaints about stuck or missing deposits and withdrawals, the mysterious CEO, the virtual company address, rumours of insolvency...
Well now the website's down and a hack may be blamed, whether true or not. Just like with Mt.Gox and Crypsy. My money's out, but I'm hoping I'm wrong and friends and family haven't been robbed.
If Poloniex comes back online and you have access to your wallets, for god's sake get it out. There's more than enough warning signs whether it's malice or incompetence that your cryptos aren't safe there. Either way it looks like a sinking ship.