Efficiency increases demand. Energy efficiency, long held as the best way to reduce energy use, doesn't. But U.S. annual energy use has grown by the equivalent of 2.5 billion barrels of oil over the past 20 years. Efficiency reduced the cost of energy. This is good.
Energy use falls only in a stagnant or depressed economy.
Cyberspace won't reduce oil use. The Information Age will increase our use of oil. For one thing, information technology functions like an economic lubricant. Economic growth, especially in developing nations, means more energy use, if for no other reason than people will buy cars as soon as they can afford them. Then too there is the universal lock-step relationship between economic growth and electric use, which drives a global appetite for conventionally fueled power plants.