It’s difficult to tell the size of a virtual world unless the creators tell you. Blizzard, the creators of World of Warcraft, have not let that information out and it has led to some experimentation by players. Most recently Tobold attempted to measure one of the landmasses using a character.
To measure a square mile, you first need to define what a mile is. As “a mile” doesn’t even have the same length on different places on our earth, that isn’t trivial. The basic definition of a mile is coming from Roman times, defining a mile as 1000 double steps of a marching legion. The soldiers had to walk through all of Europe anyway, so you just needed to count their steps and had the place all measured up with few extra effort. Clever guys, these Romans. But on Azeroth “steps” aren’t that easy to count, and the length of legs between the different races varies widely. But interestingly all races move at the same running speed, so it makes sense to define the mile by the time it takes to run it. On earth, a marathon runner has a running speed of about 12 miles per hour. As everybody on Azeroth is a hero, lets just define the Azerothian running speed as 12 mph as well. This effectively defines an Azerothian mile as “the distance you can run in 5 minutes”, without using any speed enhancing items of course.
Based on his measurements the island of Kalimdor is about twice the size of Manhattan, not very big at all. If you are looking to see what the islands look like you can check out World of Warcraft Maps (note it doesn’t have a scale).
There are interesting things happening at the intersection of geo and virtual worlds all the time. At Where 2.0 2006 we had the Electric Sheep Company discuss their Second Life-Google Earth viewer. Maybe we’ll explore WoW this year.