You can trade it on that new exchange they listed on: mxc.com.

I sent a small amount of steem over the other day and traded it, but haven't attempted to withdraw yet. I'll send a bit more over in a few hours when my powerdown is complete to test it out.

btw - on MXC you can only trade steem for tether atm. I traded some and immediately converted to ETH. They charge 0.005ETH for a withdraw and have a minimum withdraw of 0.05.