I hope volume stays on Poloniex. They were the first to add XEM just like they were the first to add Monero and other cryptonote coins. It's a better exchange than bittrex anyway.
Poloniex is the best alt exchange, imho, and a real model for how crypto should be - they have good programmers there, they tend to focus on high-quality, innovative coins before anyone else does (not garbage clone coins) and they seem to be a lot better at hard-core development and coding/integrating new coin codes than anyone else.
I've noticed that, even when Mintpal was around, Poloniex tended to iterate new features on the site (like easy/fast searching for coins in the right sidebar) a lot faster than anyone else (Cryptsy has yet to join the 21st century in that regard). Minor changes for the most part, but they seem to make those minor changes with quicker ease than other altcoin exchanges.
Plus, they handled the only big hack they had early on really well - with a lot of transparency and integrity. And they returned everyone's BTC.
And their trollbox was a very early source of high-value real-time intel (especially back when crypto was more active and there were a lot more conversations going on) instead of having to trudge through bitcointalk all day long.
Plus the way they handled the anouncement of their redesign - unlike Mintpal, they didn't spend weeks hyping about a future redesign. They just freakin' did it and stunned everybody. They don't spend weeks/months hyping - they just deliver.
They really don't get enough credit, imho.