Poloniex took BTC from the users who had money on at that moment. They promised to pay it back pay in 10 installments( payed 5 or 6 installments till now).
Trading is going normally and there were no major problems since then.
Thanks for your lightning fast reply.
I get that trading might go "normally" but my question is more about deposits and withdrawals, if I deposit btc will all of it get credited, and if I want to withdraw btc will all but the withdrawal fee be allowed to leave?