Another form of retargeting, and also perhaps the most common of them all is site retargeting. This takes place whenever a visitor has been to your site before, and ads are shown to the user depending on their visit, or on individual pages from your website. This form of retargeting is cookie based and the ads are free to appear throughout the ad network. You can toggle settings to only display ads whenever a page has been visited or the user carried out a particular action.