Why Do Google Maps's City Labels Seem Much More "Readable" Than Those of Its Competitors: Bing Maps or Yahoo Maps? First look at the Google Maps:Here's the answer:
And, here's the answer:
"The white outlines of Google's city labels are thicker, and you can't see maps' background details (roads, rivers, etc.) behind them. [...] Google typically uses more classes of city labels, at a time, than the other two sites. [...] While the primary difference between each site's city label classes is their size, Google takes this one step further by also using color to differentiate its city label classes. In that, the smallest city labels on Google's maps are significantly lighter in color than the largest ones. These lighter labels, in turn, enable smaller cities to fade into background, while allowing the larger cities to stand out."