How does the US tax its citizens?
The US is the only developed country in the world where your tax duty is based on citizenship rather than where you live or work. This implies that every US citizen (also those with dual nationality) wherever they are born, based or work, has to file US taxes yearly. Whether this implies a tax payment in the US is strongly dependent on your personal situation. Not filing taxes in the US is considered a criminal offence.
The question of whether the US should now switch to the residency model has been generating more debate in recent years. Particularly as the US has stepped up tax enforcement on its non-resident citizens with FATCA. Americans Overseas are renouncing their citizenship in greater numbers over the last couple of years.