He quotes a speech by Michael T Jones, CTO of Google Earth, who in a talk said:
Google has been sending GPS kits to India that enable locals to make more detailed maps of their area. After the data has been uploaded and then verified against other participant's data it becomes a part of the map.
Pretty interesting stuff. Read the whole post for more information.
Now, everything you see here was created by people in Hyderabad. We have a pilot program running in India. We've done about 50 cities now, in their completeness, with driving directions and everything - completely done by having locals use some software we haven't released publicly to draw their city on top of our photo imagery.