Google Maps Sneek Peek

Search – Google Maps Sneek Peek
*Google are testing and this may not be available to all web users…

Highlight the map area of interest by search.
Switzerland Map Box Boundary
Useful for Countries, Administrative, City Limits and even Islands.

Great for people who are looking but don’t necessarily now the shape or administrative regions Zipcodes in the US, Postal Codes in Canada (but not UK postcode sectors).

Google are testing a highlighting method for the users search
London Map Box Boundary
London (Westminster London) is automatically highlight when users do a search on google.com

sources:
http://searchengineland.com/google-adds-zip-code-outlines-to-map-one-box-77733
http://googlesystem.blogspot.com/2011/05/google-maps-onebox-outlines.html