What made the Great War a war on an unprecedented scale?

WW I, also known as the Great War (or in Russia, the Great Patriotic War) was unprecedented because it was the first major war fought with industrial age technology. There had been some very large wars in the past, but they were fought on horseback, or on foot, not with trucks and planes and trains and so forth. Modern technology increases both the speed and power with which armies can attack other armies or civilian populations. Added to the technological element is the size of the empires involved. WW I involved a higher percentage of the world's population and geographic locations, than any previous war. It truly deserved to be called a world war. All previous wars, however large, did not involve the whole world.