The Fog of War was also the name of the feature in Warcraft 2 that did not allow you to see all of the map that you have not explored, or currently were not occupying. This was a technique to add uncertainty to what your opponent was doing, and where the enemies were (it probably was conserving memory as well). Most RTS games followed this feature, making it one of the most copied ideas in computer-based strategy since. Warcraft 2, the maturing element of the Real Time Strategy genre, introduced this and a lot more elements into the modern RTS games. It still remains today one of the best balanced, simplest, and down right most fun multiplayer games to date, due to innovative features like that.