The document discusses location-based services and marketing using location-based apps like Foursquare. It provides details on how location-based services work using GPS, cell tower triangulation, and WiFi hotspots. It also discusses different types of location-based apps like maps, games, and social networks. Finally, it outlines tactics for location-based marketing and provides a case study example of how a brand used Foursquare to increase foot traffic by 33% and gain new fans/followers.