This isn't a big issue, as far as I'm concerned, we already closed our account at Poloniex a while back. Their service had become terrible (deposit/withdrawal paths were often down).
And most recently, they dropped support for a number of coins, including Steem. I guess all that may have been related to this sale of the company (or "spin out", as they like to call it, since there's a larger company, Circle, that had bought Poloniex a while back).
I'm pasting the contents of the email I received, as it might be of interest to non-US people as well, who won't receive the email, I suppose (or if it lands in your spam folder, like my copy did):
Hello Poloniex Customer,
We are writing to inform you that Poloniex is spinning out from Circle into a new company called Polo Digital Assets, Ltd. This new company will have the full backing of a major Asian investment group, who intends to focus on the needs of global crypto traders.
Unfortunately, the Poloniex spin out will not include US customers, so Circle is winding down access to the Poloniex exchange for you and other US customers. Here is the wind down schedule:
October 18, 2019, US persons will no longer be able to create, or complete the set-up, of a new Poloniex account.
November 1, 2019, you will no longer be able to execute trades and should no longer deposit assets.
You will be able to access and withdraw your cryptocurrencies, through Circle until at least December 15, 2019.
The full announcement can be found here and our Customer Support Team is available to answer any questions you may have. Simply reply to this message and we will get back to you.