We want to view the changes in an area, like the itoworld tool does, but as a central part of the system. http://www.itoworld.com/static/openstreetmap_tools/osm_mapper.html we need to be able to subscribe to the changes as a georss feed
you could post the basic data about an osm changeset using a short bounding box the basic data in it and a link to the data in twitter and then aggregate the data. this could use a geohash or something similar to easily select the area.
n80: we'd need to keep track of which changesets had been applied and which not
and which are remapping or deletions and should definitely not be applie