In case you have not been paying attention, I changed the layout of my blog a few days ago. The picture that I use in the header can be found here, and this is the corresponding explanation from NASA:
This is what the Earth looks like at night. Can you find your favorite country or city? Surprisingly, city lights make this task quite possible. Human-made lights highlight particularly developed or populated areas of the Earth’s surface, including the seaboards of Europe, the eastern United States, and Japan. Many large cities are located near rivers or oceans so that they can exchange goods cheaply by boat. Particularly dark areas include the central parts of South America, Africa, Asia, and Australia. The above image is actually a composite of hundreds of pictures made by the orbiting DMSP satellites.
Evidently, electricity is important and oftentimes it is used as a proxy for economic production when reliable data is not available. Electricity also tracks economic development rather nicely. So, if you ever wondered whether the western/capitalistic world really faced a threat from former socialist countries, just look at the picture one more time: empirical observation beats ideology, anytime :)