Hack, not exchange.
Biggest in terms of the value of the coins.
If you ask 100 people in my country what is Costco or Tesco probably 1 of them will know the answer (and I'm from Europe)
Stop looking at the fake volume on CMC, they started a lot of deals with 3rd parties in Japan including physical stores after the hack and got bought by a serious investor so it might be that the "hack" was actually a real hack.
Since they started reimbursing the money (at the value of the hack, and the value decreased a lot since then), the FSA gave them their license and ok, seems like I was wrong about them a year ago when I too screamed fishy!!!