Yes, sad news about Poloniex. Might I suggest using wavesdex platform for DNotes trading.
Looking into it a bit more. It seems as though you can deposit / withdraw a couple of currencies, such as Waves/Bitcoin/Litecoin/Ethereum. The deposits are turned into representative tokens, and the actual deposits may be managed by waves. Other tokens appear to be user generated tokens, even if they are representative of other actual tokens. If you are more familiar with their platform, what I need to figure out is how exactly DNotes could be included in their exchange.
Check out KMD's (SuperNet) Barterdex exchange as well. There is currently a command line version and I think GUI beta is also available. These exchanges are the future of decentralization. Something to keep an eye on. There are already quite a few coins signed up. JL777 is amazing.