Google Maps Implementation
When you drag a Google map, the grid squares are downloaded from the server and inserted into the page on your web browser. If you search for a business, the results are downloaded into the side panel and map without reloading the page. Locations are indicated through dynamic rendering of a red pin composed of several partially-transparent PNGs on top of the map images.
Google Maps uses JSON for data transfer rather than XML, for performance reasons, under the umbrealla of the Ajax project.