The entire world seems to be heading toward points of inflection. The developing world is embarking on the digital age. The developed world is entering the Internet era. And the United States, once again at the vanguard, is on the verge of becoming the world's first Entrepreneurial Nation. At the Chicago World's Fair in 1893, Frederick Jackson Turner delivered a paper to the American Historical Association – the most famous ever by an American historian. In "The Significance of the Frontier in American History," he noted that, according to the most recent U.S. census, so much of the nation had...