Recently Google filled a patent on serving dynamical offers using the position of the user. The main principle is that of offering driving or walking direction to the user, detailing the resources at the end point of the direction and along the way. Seo by the Sea explains in details how this can work.

Generating and/or serving dynamic promotional offers such as coupons and advertisements

Inventors: Ashutosh Garg and Allen Romero

US Patent Application 20060143080

Published June 29, 2006

Filed December 29, 2004

Abstract

A promotional offer may be generated by (i) accepting information concerning at least one of (A) a search query entered, at a client device, by a user, (B) an item or establishment which is the subject of a search result selected by a user using a client device, (C) one or more items or establishments which are elements of a shopping session summary provided to a user via a client device, (ii) determining a promotional offer to serve using at least the accepted search query information, and (iii) determining terms of the promotional offer using at least one of (A) a location of the client device, (B) a distance from the client device to an establishment associated with the promotional offer, and (C) a distance from the client device to an establishment competing with the establishment associated with the promotional offer, (D) an inventory, at an establishment associated with the promotional offer, of the goods which the promotional offer concerns, (E) a capacity, at an establishment associated with the promotional offer, to provide the services which the promotional offer concerns, (F) a level of excess capacity, at an establishment associated with the promotional offer, to provide the services which the promotional offer concerns, (G) a perishability of goods which the promotional offer concerns, and (H) a remaining shelf-life of goods which the promotional offer concerns.