According to Wikipedia
Behavioral retargeting (also known as behavioral search retargeting, or simply, retargeting ) is a form of online targeted advertising by which online advertising is delivered to consumers based on previous Internet actions that did not in the past result in a conversion.
How does it work?
You visit a site, look at some products, maybe add some of the products to the shopping cart but then decide not to buy them because you need some more time to think about it. You close your browser and are done for the day. Next morning you go back to your computer and browse to a news site. As the page of that site loads so does an Ad that is from the site that you visited yesterday (where you looked at some products but did not buy)
Neel visited Sketcher’s site (They engage in retargeting – http://www.mediapost.com/publications/?fa=Articles.showArticle&art_aid=109038. He looked at few shoes, added one to his cart but then decided that he is going to look some more before he buys them. He was tired after long day so he decided to logoff from his computer and takes some rest.
Few minutes later he gets back on his computer but before he goes and checks more shoes, an article about online privacy in an email catches his eyes so he clicks on the link to open the webpage to read that article. As he browses to that article on NYTimes.com, he sees an ad from sketchers on that same page. The page content has nothing to do with the shoes but the person reading it has. Sketchers is retargeting to bring back the visitor who had left the site (sketchers.com) without converting (purchasing). The main idea behind retargeting is to reinforce the brand message and bring the visitors back to the site so that visitor can convert and become customers.
How does it work technically?
Behavioral Targeting 101
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