Interesting that this map so closely matches a recent map (US-only) that shows population density with one dot = 1 person. (http://bmander.com/dotmap/index.html)

In the NASA Map, it's probably more like 1 light = 100 people or whatever, but it still seems pretty clear that with few exceptions, population = light.

The exceptions (like the Australian Outback, presumably) are even more interesting, however...

Carnegie Station is 700km east of Carnarvon WA; easy to spot on the NASA image,
The edge of Lake Carnegie 100km South West of the Station is easy to see.
The station blog for Oct/Nov makes an interesting read:
"Fires have kept us very busy more recently.... even with the station evacuated for a small time lots of fire preparation tidying up fires breaks etc ... Fires caused primarily by lightening strikes we get lots of dry storms out here and its not uncommon for the lighten to hit the spinifex and with no rain fires are quick to start. The fires have been burning for weeks on end ....they seem to be coming under control now... However weeks into the fires ....
http://www.carnegiestation.com.au/blog.html

For an explaination on the outback lights; read here:
http://www.spacedaily.com/reports/Wildfires_Light_Up_Western_Australia_999.html