Geographical distance is as strong a determinant of economic exchange as it was a half-century ago. Even the Internet, it turns out, is not as borderless as it seems: one study found that Americans are much more likely to visit Web sites from countries that are physically close than from countries that are far away, even after controlling for language, income, and many other factors.
地理距离也跟半个世纪前一样深刻影响着经济交换行为。甚至连互联网也不像想象中那样没有边界：一项研究发现美国人更喜欢访问那些邻近国家的网站，即便在排除了语言，收入和其他因素的影响之后也是如此。