Commodities: In the business world, a commodity is an undifferentiated product whose market value arises from the owner's right to sell it rather than the right to use it. For example commodities from the financial world include oil (sold by the barrel), electricity, wheat, bulk chemicals such as sulfuric acid and even pork-bellies. More modern commodities include bandwidth, RAM chips and (experimentally) computer processor cycles, and negative commodity units like emissions credits.
 

Online Trading article 100 - "The New Landscape Of Online Trading" article from WSJ