Night Lights

This image is from NASA's Earth lights satellite composites. It's amazing that electricity was invented over 100 years ago (a blink in the span of time) and we've lit nearly every corner of the Earth (despite it being a sphere ;).

I wonder how big of a light it takes to show up on a satellite image? For instance, what is in the middle of the Atlantic Ocean, just east of the US? Other things to notice: Russia has built an extensive network to Siberia; the Nile is a solid bright line; Australia - not as bright as one would expect; and Canadians apparently live mostly on the US border, but who can blame them, right?

The question is: is this a positive achievement or some disasterous consequence of urbanization?