The bird's-eye view (or aerial view) has been a feature in CAD software since the 1980s. I recall when Artist Graphics (part of Control Systems) released their AutoCAD display driver with the BEV feature. Autodesk later incorporated it into AutoCAD as the DsViewer command. I don't know that anyone uses it, but I've suggested it could be opened on a second screen to give an overview of the entire drawing.
Anyhow, Google Maps now has the bird's-eye feature (along with new, detailed maps of Germany, useful to me, since all my relatives live there). In the lower right corner, a small rectangle shows a larger area of the map, along with a rectangle indicating the current zoomed-in view.
I can't figure out how Google Maps determines the area to show in the BEV -- the previous zoom level? The smaller rectangle can be moved with the cursor to pan about the region.
Not related to maps, but Google's market share for Web searches increased to 49% last month, and it's not a hard stretch seeing it breach majority territory (>50%) soon. In contrast Microsoft's marketshare of search continues to fall, now down to 11% -- even though it is the default search engine on all newly-purchased Windowized PCs. Yahoo holds onto the middle ground.