Poloniex Owners Know things that you Don't
Poloniex is owned by Goldman Sachs... and... others. If Poloniex is regulating itself, it's because it knows regulations are coming. The people who own Poloniex are the same ones who write the regulations for the federal government. Therefore, they are prepositioning themselves to operate in the US in a compliant way.
Poloniex is the Bellwether
Poloniex is big money. When you see Poloniex in the top five of exchanges, you can know that the period of price manipulation over Bitcoin is ending. MY OPINION (not financial advice): when you see that happening, you should buy up as much Bitcoin as you can get your hands on, because it's about to blow up.