SAN FRANCISCO (AP) -- Determined to sell more television ads, Internet search leader Google Inc. is sharpening its focus on the medium with demographic data from the influential Nielsen Co.

Under an agreement, Google will pay Nielsen an undisclosed amount to obtain detailed information about the kinds of people who watch.
The breakdown, drawn from Nielsen's rating service, typically provides viewers' ages, gender, marital status, and other personal data that help advertisers choose the audience most likely to be interested in their product or service.
New York-based Nielsen has been selling demographic data to television stations and advertisers for years.
Google's access to the information is significant because it gives the Mountain View-based company more tools to draw upon as it tries to target television ads as effectively as it has done on the Internet.
Because it processes more than 1 billion search requests per day, Google hasn't needed as much outside help to learn about the interests of its Internet users.
Since May, Google has been delivering television ads for about 14 million subscribers to EchoStar Communication Corp.'s Dish network and Astound Broadband cable service.
The set-top boxes used by EchoStar and Astound enabled Google to track when commercials were watched and for how long. By drawing on Nielsen's data, Google will now have information on what kinds of viewers are watching the commercial.
Even as it expands its ad platform into TV, radio and print, Google continues to make most of its money from text-based ad links posted next to search results and other online content.
Google's formula has been so profitable that it now has a market value of about $210 billion, second only to Microsoft Corp. in the high-tech industry.
The Google alliance appeals to Nielsen because the rating firm is trying to develop new measurement techniques and extend its reach into more digital media, such as iPods and mobile phones.