This was presented at the Volunteer Geographic Information conference in Dec 2007, see http://www.ncgia.ucsb.edu/projects/vgi/.

The paper that TFA references can be found at http://www.ncgia.ucsb.edu/projects/vgi/docs/position/Goodchild_VGI2007.pdf

Another presentation on Openstreetmap from the same conference is at http://www.ncgia.ucsb.edu/projects/vgi/docs/present/Coast_openstreetmap-opendata.pdf