With AdWords, you can target your ads to countries or territories, or to specific regions and cities. When someone enters your keyword on Google, the AdWords system uses several factors to determine whether to show your ad:
- We consider the Google domain being used (.fr, .de, .kr, etc.). If a user visits www.google.fr, the Google domain for France, she'll see ads targeted to France, regardless of her current location.
- We analyze the actual search term the user submits on Google to determine when to show ads targeted to a specific region or city. If someone enters a search query that contains a recognizable city or region, we may show appropriate regional or custom-targeted ads. For example, if someone searches for 'New York plumbers,' we may show relevant ads targeted to New York, regardless of the user's physical location.
- When possible, we determine the user's general physical location based upon their computer's Internet Protocol (IP) address. An IP address is a unique number assigned by Internet Service Providers (ISPs) to each computer connected to the Internet. This applies to regionally or custom-targeted ads as well as all ads shown on Google.com.
- Regional and custom-targeted ads: If someone searches for 'plumbers' from a New York area IP address, we may display ads targeted to New York, even though 'New York' wasn't in the search query.
- Any ads shown on Google.com: While country-specific Google domains (such as Google.fr) don't use IP address to target ads, Google.com does. For example, if a user with an Australian IP address visits Google.com, we'll display ads targeted to Australia, even though the user isn't accessing Google.com.au.
Additionally, a user's language setting will determine which ads they can see. The 'Preferences' link on the Google homepage lets users choose the language in which they want to search. When the user sets the language preference, Google only displays ads that are targeted to the chosen language. For example, users who choose Spanish as their language preference see ads targeted to Spanish speakers. If the user doesn't specify a language preference, the Google domain (like Google.fr) determines the default language preference (in this case, French).
iPhone and other mobile devices with full internet browsers
As on desktop, query parsed location always takes precedence in determining which location to be used for serving ads on iPhones and other mobile devices with full Internet browsers. However, on these phones, we can often determine the user's general physical location from device location. Additionaly, we can infer user's general phyical location from various other sources such history of queries and carrier country. If the query does not contain a location we use a hierarchy to determine the best location signal to use.
- Device location - When a user performs a search with My Location enabled, we get more precise information about that user's location. We use various sources for device location information and always choose the most accurate source:
- GPS: Accuracy varies depending on GPS signal and connection.
- WiFi: Accuracy should be similar to the access range of a typical WiFi router.
- Google's cell ID (cell tower) location database in the absence of WiFi or GPS. Accuracy is dependent on cell tower density and available data. Some devices do not support cell ID location.
- Coverage for Google's cell ID and WiFi location databases varies by location and is not complete. We are always working to improve both coverage and accuracy over time as usage of our location-based services continues to grow.
- GMM viewport - For ads shown on Google maps for Mobile we may use location obtained from the viewport of the map.
- IP address - If a user is connected to a WiFi network we may use the IP address to determine that user's physical location. If the user is connected to a mobile carrier's proxy server then carrier IP is used to determine country of the user.
- Location from history of queries - Based on the location obtained from a user's last few queries, we attempt to guess the user's approximate physical location and use that to serve relevant ads.
