Site retargeting directs advertising to new visitors of your website, who leave without completing your intended action. When bounced visitors browse the web later, your ads will appear on a variety of websites, recapturing their interest and keeping your brand fresh in their minds, resulting in them returning to your site.
Most marketers find that they see the highest ROI from retargeting than from another channels. This is because the adverts target people who are already interested in your brand and are familiar with what you provide.
Retargeting is automated so that the whole process occurs within less than a second. In the time that your bounced visitor loads another page, the purchase of the advertising space will have been completed for your advert to immediately appear with the rest of the content on the page. The COOKIE informs you when a bounced visitor clicks onto another website and if an ad space is available, it will make a real time bid. If your bid is the highest, you will secure the space for your ad to be shown.