"Interest categories" beta on Google Display Network was announced a in March 2009. Today, Google's Inside AdWords blog announced that the interest categories are now available to all AdWords advertisers.
"Our system looks at the types of pages a user visits, taking into account how recently and frequently those pages have been visited, and then associates their browser with relevant interest categories. Using these categories, you can show ads to the people most likely to purchase your products or services, and you can reach them across all types of sites in the Display Network in addition to contextually relevant sites," explains google.
"With over 1,000 interest categories from ecotourism to mobile phones, we're confident you'll find a category that fits your business. And with over 500 million users interested in these categories who visit GDN every day, you'll be able to reach a huge number of potential customers. You pay only for clicks or impressions at auction prices, as always."
"Our beta advertisers have used interest categories to successfully meet all kinds of goals, from an advertiser increasing brand lift by 40% to a shoe retailer driving 400% more conversions at a lower advertising cost per sale," stated Google.
"Users may, at any time, view and edit interest categories or permanently opt out of receiving interest-based ads entirely with the Ads Preferences Manager. Also, we label our ads with the AdChoices logo to give users notice and choice about the ads they see," added google.
You can visit Help Center to learn more.
[Source: Inside AdWords]