Till now Google Adsense was using Placement-targeted ads, now it has launched interest-based Ads (beta) in it’s network. These ads will associate categories of your interest — say Technology, Sports. These interest are based on the types of sites you visit and the pages you view, while placement-targeted ads reach users visiting specific sites, independent of their interests. Check out difference between Placement-targeted ads and Interest-based ads.
How interest-based Ads ?
As you visit websites in your browser, Google stores an advertising cookie in a user’s browser to understand the types of pages that you are visiting. This information is used to show ads based on interest categories that might appeal to your users. Your interests are associated with an advertising cookie that’s stored in your browser.
For example, If you browses many technology related websites, Google may associate a technology interest category with their cookie and show the user more technology-related while displaying AdSense ads.
Users can view edit list of interest categories within the Ads Preferences Manager. Users interests are associated with an advertising cookie that’s stored in your browser. If you don’t want Google to store your interests, you can opt out here.
Publishers
Adsense Publishers don’t need to change the ad code on their website. You can opt out of interest-based advertising in your website by login into adsense account. Interest-based advertising are served to users based on their interests and may improve your earning potential over time. Users interests are associated with an advertising cookie that’s stored in their browser.