To go back to AT's original question, I would say an extensive thermodynamical variable is a good, and an intensive variable is a service.

Examples of goods: (Thermodynamic Free) Energy, (neg)-Entropy, Space/Size, (amount of) Matter, electrical charge/current, magnetic moment (i.e., strength of a magnet).

Examples of services: Temperature, Pressure, surface/linear Tension, electrical Voltage, magnetic Field.

Hah.

Most economists teach a theoretical framework that has been shown to be fundamentally useless. -- James K. Galbraith