As well as Street View, Google could decide to add Audio View, then use this to make sound maps.
In order to make this effective, several recordings of ten minute clips would need to made at a various parts of the day in the locations chosen. These would include quiet city streets, noisy main roads,
shopping areas, parklands, seasides, and other rural places, but also include barren places, jungles, forests, farm-land, industrial sites, and even war zones.
Everywhere has its own noise signature, which constantly varies, so not only would a daily variation be required, but seasonal ones too, so that migrating birds could be heard, or the wind howling through a fence somewhere, or drunks spilling out of a nightclub. You pick your place, then your date and time, then sit back and listen.
Want to know what Broadway, New York sounds like at 2 am on a Saturday night around 14th street? or how about the Masai Mara game reserve at 4.35pm in a tropical rainstorm?
Next time you see the Google Street View car parked somewhere, take a good look at its extendable pylon to see if it is in fact a microphone cluster.