It says right on the bottom right corner of the map where the map data comes from. NAVTEQ & Teleatlas. The same people responsible for (arguably) the best in-car nav systems: http://www.navteq.com/ It's practically the same experience (map viewing when you zoom in) as the in-car nav systems they make.

"Keyhole" doesn't own any map IP. They just buy data from providers and link it all together.

Bruno