I thought the article was pretty clear that Hacker News user base is predominantly North America and Europe, not just the valley?
I don't have any data to back this up, but based on the sources that are posted and gain traction in the community, I suspect majority NA & Europe is accurate. But that's just an observation based on my personal experiences that different regions of the world view information sources differently in terms of reputation and trust.
Has HN or anyone else ever tried to aggregate stats on content sources or user location data?
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)