Great work @rj on mapping. I've added your link to the first post for easy reference.
Here are some instructions @rwn wrote that other players might find helpful for adding tags to the map.
As far as I can remember, you need to log out of google to see every tag (once the game is some hundreds of tags and the list of points on the map spans several pages), also this avoids accidentally moving them I think; I never got into helping with the map. Correct me if I'm wrong.