NEW YORK -- Google is giving online merchants and other Web sites more options for tailoring their advertisements to local audiences.
Under a new program set to begin Thursday, a pet store in Boston, for instance, can specify that it wants to reach Google users in the Boston area only. Or a national company can have different ads run in San Francisco and Washington, D.C.
The new program affects the ads that run on the right side of search results, although Google is separately testing a local search service to customize the regular searches as well.
Previously, businesses could specify only what country they wish to target, making the program prohibitively expensive for smaller merchants.
"Users will be better served with local business results," said Salar Kamangar, Google's director of product management. "We see it as a way to bring in useful local business relationships into the search process."
Advertisers targeting the United States, Canada, the United Kingdom, Germany, France, Italy, Spain and the Netherlands have the most options. They can specify cities or metropolitan areas they wish to target.
Elsewhere, merchants can enter their address and a radius, in miles or kilometers, around which to target. So an Indian merchant can type in a New Delhi address and have the ad appear on computers located within 50 kilometers of the business.
Web sites can also target ads based on their latitude and longitude.
Google generally knows where a user is, based on the Internet Protocol, or IP, address associated with the computer being used.
Although technology for IP targeting has improved greatly in recent years, there are still cases where a location can be determined no better than a country or state. In those cases, Google would not display any localized ads to ensure greatest accuracy for the ads that do appear, Kamangar said.
Kamangar said Google will also guess location based on users' search terms, and users can enter that information when they test the local search service.