infogargoyle has a post about mapmaking, in particular the use of RDF to collaboratively define space. I’m surprized that a strong open source community hasn’t already started to form around mapping for mobile devices. Maybe it has and I just don’t know about it yet? I see projects like OpenGIS and GeoURL (unfortunately down right now, but that’s not my real point) and I see what seems to be a great set of building blocks. If we could get the basic map down, and from what I heard there were some people lobbying hard to get better map data for the US put in the public domain, a service like GeoURL that gives you local points is a great start. If those points could be filtered by trust of the source, or even beter FOAF type analysis out to some sane degree of connectedness, I think we would have a great app right off the bat. And of course, once you have a good starting point, that’s when people actually get interested and start filling in their own points of interest.