There is such an obvious bias in the data to Western Europeans and North Americans that I wonder at the hubris displayed in titling this as "Humanity's cultural history".
The most shocking was when they said that the important people in 17th century Japan were all missionaries... surely some of the least important people in the country at that time!
They mention their source for notable people was Freebase, which iirc use DBpedia which in turn uses English Wikipedia. This is the source of the bias. I do not know if information from the other Wikipedias is available via Freebase.
But I think you're right that it would be useful to note at least somewhere close to the title that the provenance of this data skews it quite a bit.
Edit: the paper itself is centered around providing this framework for looking at cultural history. The author of the blog post for Nature is the one who made the over-reach in the title.
Yes. My first thought was "I'd like to see this for India and China". Or the Arab world. Or the Mongol khanate. The unfortunate truth is that's not going to happen, partly because the position of the individual in western societies and their history is a lot higher than in many historical societies. In one example I know, the Chinese moved entire armies west to conquer sophisticated neighboring civilizations rather than individual settlers. Further, their governance/aristocratic classes were frequently rotated through far-flung locales to prevent local power bases from developing. I suppose these sorts of properties of available data are why the visualization focuses so heavily on the later historical period and the west... afterwards, it breaks down: later on due to cheap mass travel, and earlier due to significant and real movements (eg. return voyages to the Americas from Portugal, Spain, Chinese or Indian history, etc.) not showing up. Another interesting property I noticed was the clustering in Western Europe: Paris, London and Holland/Belgium far outweighed anything else, including Spain and Portugal.
