"As you may know, Google Maps uses the Mercator projection. So do other Web mapping services, such as Bing Maps and MapQuest. Over the years I’ve encountered antipathy toward the use of the Web Mercator from map projection people. I know of two distinct schools of opposition. One school, consisting of cartographic folks and map aficionados, thinks the Mercator projection is 'bad': The projection misrepresents relative sizes across the globe and cannot even show the poles, they are so inflated. The other school, consisting of geodesy folks, thinks mapping services have corrupted the Mercator projection, whether by using the wrong formulæ for it or by using the wrong coordinate system for it."
Via Seth Dixon