I've been saying in keynote talks for years that users are the local experts and that a rich and accurate map of the world must therefore reflect user's knowledge. We have launched a long series of enabling tools and systems toward this end:
* Places of personal interest in the Google Earth Community at http://bbs.keyhole.com* Easy personal map annotation, sharing, and collaborative editing in Google Maps' MyMaps
* Simplified building/campus/city model creation and sharing via SketchUp and the 3DWarehouse at http://sketchup.google.com/ and http://sketchup.google.com/3dwarehouse/
* Geo-located visual place descriptions via http://www.panoramio.com
* Geo-tagging of photos in PicasaWeb at http://picasa.google.com
* Geo-tagging of videos in YouTube at http://www.youtube.com
* Business-owner creation and editing of business listings at http://www.google.com/local/add
* Public transit agency sharing of schedule data at http://maps.google.com/help/maps/transit/partners/
* Easy construction of base-map data by users and governments at http://www.google.com/mapmaker
* City/County/State/Department/Country map content data sharing partners at http://maps.google.com/help/maps/mapcontent/
* Other efforts under development and test but not yet launched publicly.
Step back and look at this broadly. Google Web Search products index the world's websites. Everybody understands that role. Google's geo team would ideally simply index the world's geospatial information in the same way. Unfortunately, that data has been inaccessible, disorganized, offline, restrictively licensed, or otherwise unavailable. (NSDI efforts reflect this situation.) We licensed a broad "starter set" of data and have been busy building tools to augment that. The latest step with the recent launch of new map tiles reflects our judgment that a tipping point of data quality and cross-checking has been reached in the USA.
I know that users are now better served with an easily correctable, rapidly updatable, widely usable base-map built from the synthesis of hundreds of data feeds, hundreds of thousands of individual contributors, and potentially, hundreds of millions of local-expert users. Think of it this way. If tomorrow every Web user in the USA took one minute to look at their neighborhood or workplace on Google Maps and make any necessary corrections, every Internet user would then have access to an up-to-the-minute national map for the first time in world history. This is how it always should have been and I'm glad that it has finally happened and excited about what the future holds.