Where do TrailRunners live?

As one might expect, the TrailRunner community is very international. Thanks to google, I can present you a Geo Map Overlay for TrailRunners, a graphical representation of the volume of visitors coming from locations around the world. The darkest spots indicate locations driving the most visitors to the TrailRunner website.
Interestingly most of my visitors come from Europe, but why is that so? Americans, put your shoes on…!