The geo-targeting feature allows you to customize your ad so that it only appear to searchers from a specific location. The ad server determines the location of the visitors based on his IP address or the GPS data. You can set the location to a city or state or country. You can also set which places town, state or country you don't want the ad to appear. Location based ad can help you to get better conversion and more sales because people usually expect to see local results when they perform a search. Social networking sites such as Four Square and Gowalla also enable merchants to target customers in their locations.