Geo Messages concept proposes adding location data as signatures to messages. And this model could be actually embedded into some vertical applications (services). Here is an example - InCar emergency.
This mashup provides a generator for in-car emergency communications. Service provider (renting agency) prepares a communication script for cars owners. This script contains some predefined-data (car model, year) and uses GeoMessages for adding location info during the deployment. Such script could be preloaded to driver’s phone or placed via QR-code right in the car. It is a fast way for emergency communications.
P.S. in the more generic form the similar approach provided in Geo Post mashup that lets add geo-located messages to blogs.