I'm not sure about what the website that you are talking about, but there is another method to see the same thing. Google Earth has a feature that allows you to place geocache points on the map. It will search for all of the points for the area that is showing. You can zoom out to whatever altitude you want.... This might be somewhat the same...
This one, I thought it was geocaching.com had a map of the whole world at once and someone had put highlights for ever geocache in the world. It was a static image.