Both deposits and withdrawals for STEEM and SBD on Poloniex are not being processed since two days. Deposits are not being credited to your Poloniex account and withdrawals are not sent. Poloniex has had issues with the STEEM wallet before, but this time they don't even give us a warning. They should temporarily disable deposits and withdrawals as long as it doesn't work, but after two days they still haven't taken any action yet. There are reports that they don't respond to support tickets either.
As you can see on https://steemd.com/@poloniex many Steemians are still trying to deposit their STEEM on Poloniex. A total of 26,033 STEEM was transfered to Poloniex yesterday. Hopefully the amounts will be credited to the appropriate Poloniex accounts as soon as possible.
The latest withdrawal from Poloniex to a STEEM wallet was on 2017-12-06 09:42:36 UTC which was included in block 17,844,716. All withdrawals after this date are still on hold.
I would like to see STEEM added to more exchanges. Binance for example has 180 coins available to trade, but STEEM is still missing. Maybe we, as a community, should all ask them to add STEEM? I've just sent my request to support@binance.zendesk.com.