Fifteen years ago, advocates of the flat tax had lots of supporting theory, but very little firm data. Milton Friedman had championed the flat tax, and Alvin Rabushka and Robert Hall of the Hoover Institution authored an elegant book detailing how a flat tax would work, but the political establishment largely ignored these efforts. Hong Kong had a flat tax, but critics said it was somehow a special case. Two other British territories, Jersey and Guernsey, also had flat tax systems, but the outside world was (and largely still is) unaware of those systems.
The world has changed. Today, spurred by tax competition, there are now 16 jurisdictions that have some form of flat tax, and two more nations are about to join the club. With the exception of Iceland and Mauritius, all of the new flat tax nations are former Soviet Republics or former Soviet Bloc nations. This is a sign of tax competition in the region, and shows that people who suffered under communism are less susceptible to class-warfare rhetoric about “taxing the rich.”
The World is Flat Taxed
Here's an interesting article from American.com on flat taxes (please, no remarks on the potential oxymoron):