OpenStreetMap Then and Now
FWIW, the maker of this (Martijn Exel) gave a talk on where to improve OSM last saturday in Seattle at the OSM 10th anniversary event. Slides from his talk are here: https://docs.google.com/presentation/d/1ey85IHqupj7aWxq92Rzq...Personally like his other tool, the OSM vs. US Census Tiger 'battlegrid' : http://184.73.220.107/battlegrid/#10/41.8941/-87.7753