The timelapse video below illustrates Madurai, India being mapped:
Only certain regions of the world are available to edit/map, for obvious reaons, a complete list of areas can be found on the Map Maker site.
The next video details Nicosia, Cyprus:
Google explains the concept of Map Maker below:
Its quick, easy, moderated and provides a publicly viewable basemap in areas where mapping maybe limited. If you are logging in from a part of the world not covered by Google Maps then Google Map Maker is well worth a look...