Do you mean, you will use in margin trading? AFAIK, poloniex is offering this margin trading.They will let you borrow and trade but you can not withdraw it unless you stop margin trade and settle.
but be careful, if you don't have experience on trading or you are new in trading, you can not make money. beside that, if you only have small funds to trading with margin trading, i think its hard to make a big money.
Thanks for the advice, I never tried margin trading either.
I and I am not confident to used it. I just park my funds in lending section there to be used by margin traders. Though it earn a minimal interest,its ok for me.