Earlier quoted context omitted.
Here's a local law where if you meet all the criteria (income made off the island, spend > 180 days per year here, various other criteria), you're exempt from income taxes here. And since you're a resident, all your income is here. Effectively exempting you from federal income taxes. The idea was to attract high net worth individuals to spend money here. Every analysis I've seen says it has worked quite well.
Crazy. So if you move to PR but making money from other US based interests you get exempted from US federal income tax, but if you move and work permentantly in say Germany, you still get charged US Federal Income tax?
I'm not familiar with the Puerto Rico situation, but elsewhere, some (likely significant) portion of your foreign-earned income may be excluded from your US tax burden. For most people who earn money abroad this means that while you must file taxes, you likely don't pay anything to the US Gov't on foreign-earned income.
I find the whole taxation-by-citizenship thing ludicrous and coupled with the separate Foreign Bank Account Reporting for accounts having more than $10k taxes are a headache for Americans living abroad.