Because of the way Google lays out a globe on a flat surface, horizontal distances get stretched in places. This get more pronounced the closer you get to the poles.
In the given example, in Anchorage Alaska, the intersections in the visible city zone are actually all normal right angles.
Map Distortion example (Fixed by Google)
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© Bing Maps
By TexasAndroid @ 2005-06-22 10:48:06
TexasAndroid
@ 2005-07-25 10:42:54
As of 7/25, Google has fixed all their calculations to correct the horizontal stretching. Moved this to the Updated category.