Tried a new mapping site tonight that quickly promises to show the globe as the sum of the parts of the world you've been to, albeit it in a very general way (countries as a whole, rather than parts of countries, etc.).
Here's what it says on the website where you can do your own:
Visited Countries is a small project demonstrating the power of manipulating the palette of a gif image on the fly. Here we start with a map of the world with each country in a different color. The script asks which country you have been to and sets the colors of those countries to red, the rest to green.