[PaulHoule]

For one thing, all content on HN is English, which is well-known to people in NA and Europe.

Japan is famous for its indigenous forums; Japanese people seem to sneak some English words into every anime theme song, but they do awful on the TOEFL.

When you look at South America and Africa I think that educated people are often good at English but even though there are a lot of people in those zones, the size of the "startup sector" or even the "modern sector" is small compared to NA/Europe. (e.g. look at GDP as a proxy)