In March 2009, we announced a beta of interest-based advertising, which included remarketing and interest category marketing, to help Google Display Network advertisers reach people who are most likely to be interested in their products and services.
The early results show that interest-based advertising is helping to deliver better ads and product offers for users, more effective campaigns for advertisers, and higher returns for website publishers. Remarketing was recently launched to all advertisers, and the number of advertisers using interest category marketing has continued to grow.
As part of our efforts to keep improving the product and to give users more control over the ads that they receive, we are adding some new categories that will enable us to show ads that relate to demographic categories, such as age and gender. This works exactly the same way as interest category marketing works today - we associate categories with particular browsers, based on the sites and pages visited on the Google Display Network. To infer demographic categories, Google looks at the types of Google Display Network sites visited, and compares that information with aggregated survey data on site visitation. For example, if someone frequently visits sites that have a majority of female visitors, we may associate her browser's cookie with the “female” demographic category. Then, advertisers may choose to show more ads that are relevant to women to those people as they browse sites across the Google Display Network, the same way advertisers can choose to show ads related to other categories, such as sports or gardening.
As with interest categories, users may view and edit demographic categories or permanently opt out of receiving interest-based ads entirely with the Ads Preferences Manager. The interests and inferred demographics associated with a particular browser are based on the sites on the Google Display Network that are recently visited - and not on user data - so these categories may change over time. As one of a number of companies offering ads based on inferred interests and demographics, we remain committed to providing users the highest level of control and transparency.
Interest category marketing (including the new demographic categories) remains in a limited beta, and we're working to help more advertisers run campaigns over time.