Bitfinex has sent out notice that they are going to start requesting Tax information as is required for the operation on the British Virgin Isles. While you may not be a resident of the British Virgin Isles they will share this information with your home nation for tax reasons.
Bitfinex is a large well known exchange and happens to trade crypto to crypto but also fiat currencies including, the Japanese yen, US Dollar, Great Britian Pound, and the Euro.
This Essentially means that you will start paying taxes on your fiat trades (BTC to Euro, BTC to USD and so on). This may lead to a large Exodus of users who are always trying to keep their trades private or avoid the taxes on their trades.
It is not known for which governments will try to tax you on crypto to crypto trades, I believe in the US it is technically under Bartering laws and is taxed according, this would kill margin traders and be an extra issue that many will want to avoid.