Google AdWords Interest categories allow advertisers to reach targeted audiences across the Google Display Network by allowing advertisers to choose from a list of categories — from Yoga & Pilates to Sports Memorabilia or Vehicle Shopping — and Google will show ads to people who are interested in those categories.
Users are targeted for interest categories based on their browsing history. So for example, when a user visits a partner website, Google analyzes the content of the page and site to show contextually relevant ads. Google then associates the interests with the user’s cookie. Google says that they may also use the websites a user visits, as well as third-party data, to infer the user’s gender, age category and other demographics. If the sites that a user visits have a majority of male visitors, Google may associate your cookie with the male demographic category. (Google does not associate sensitive interest categories such as those based on race, religion, sexual orientation, health or financial categories with a user’s cookie).
Interest category campaigns are a great way to increase visibility of your products or services because you can target a specific audience. Ads using interest categories reach users when they are visiting websites that may not be related to the interested category you are targeting. In other words, you can target someone who has been on yoga related websites while the user is on a website that is not related to yoga.
Interest category campaigns are a great way to supplement keyword or placement campaigns because you can reach users who are interested in your products or services even when they are on unrelated pages. This means you can reach a wider audience and generate more qualified traffic to your site.