If countries were corporations, GDP would be their added value, or "profit before expenses" (which is spent by citizens on stuff, so the profit doesn't make it to the end of fiscal year balance sheet). GDP/capita therefore represents the average purchasing power of a citizen. This is an important point: anti-globalization protestors like to say that General Electric (for example) is more economically powerful than many countries, but they compare GE's turnover or sales to the equivalent of a country's profit. If you compare apples with apples, suddenly corporations don't look so big relative to Malaysia.

Reference: "Countries Still Rule the World", an article by Martin Wolf in the FT, 5th February, 2002