I read a comment on twitter that due to the planning and launch for Hextracoin Gold, external exchanges won't be on the agenda until after the air drop is complete. I would have liked to have seen Hextra get listed sooner but they are giving us an opportunity to get free money. They probably also realized that they would have been too over exposed if they were listed on an exchange now and face the challenge of laying out the infrastructure to provide airdrops to people with coins on an exchange...nightmare! Who knows if the exchange would even give token holders their coins. So I guess it would be best to avoid the whole scenario. Just my theory.