The wait is over! As I mentioned in December, I have been working on an interactive online map, which shows you all volunteers of the OpenStreetMap world on a map. The first three layers contain the activity center of a contributor, her or his first created and latest modified node. The algorithm to determine the activity area of an OSM volunteer has been described in my publication here. I should mention that I used all changeset centers instead of all created nodes of a contributor. This way the computations don’t take as long and the process can be repeated every week based on the weekly OSM changeset dump.