A recent article in Ad Age desribes how HBOwill launch a Google Map to show places mentioned in The Sopranos. They're doing it to reacquaint viewers with a series that's been off the air since May, 2004. HBO says they're the first, but other brands outside the US are currently running campaigns using Google's sister technology Google Earth, including:
These examples show that transmedia storytelling opportunities are everywhere because audiences are everywhere.
But the real power comes from combining things like Google Maps with other location-based data, like what Best buy did for the Launch of the XBOX 360 from Microsoft last November. Because of limited supply, they combined Google Maps with their XBOX 360 inventory so customers could find out which Best Buy in their area had stock.
Dig a little deeper:
The Google Earth Blog is an enthusiast site dedicated to Google Earth and getting the most out of it.
The Programmableweb website is a resource for finding out about all the Web 2.0 API's available and mashups created with them.