I'm not too surprised that Ireland ranks first. The company I work for drooled at the prospect of opening an office in one of the hottest tech cities in the last few years: Dublin.
But why is that?
Take a look at the top 10 countries on the list. What I find immensely interesting is that not only are they hosts to various UN organizations and international courts, but not a single one of them has a strong military. Also, none of those countries have a foreign policy which aims to impose its will on other countries.
It will be interesting to see in future years how the U.S. fares on that list. My prediction is that it will drop.