Wednesday, July 11, 2018

Retargeting 101

This post was originally posted in July 2009. I am updating it again as this is a topic that I get asked a lot lately and I have also recently launched a new course on the topic. In the course I cover Retargeting Fundamentals and how to do retargting on Facebook. (purchase course on Udemy or on Global Analytics Academy) and will be releasing the one on Google soon.

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 - 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, 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 ( 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.

Shopping at

NYTimes Serves Sketchers Ad

How does it work technically?

When a visitor visits a site (sketchers in this case), the site ( runs a JavaScript from a 3rd party ad network or an ad exchange, which (the JavaScript)then drops a cookie on the visitor’s computer. This cookie is usually anonymous i.e. it contains an identifiers to identify the visitor (computer) but does not know any personally identifiable information such as name, phone, email etc. of the visitor. As the visitor browses the site this JavaScript can collect the information about visitors browsing behavior and then tie it back to the cookie. All an ad network (3rd party) knows that cookie id 123ABC67NBZ looked at some product, put them in shopping cart and then left without completing the purchase. Most likely, it does not know that cookie id 123ABC67NBZ belongs to Neel (some retargeting products now are tying PII information too but most of them are still anonymous).

If the visitor then browses to another sites on the internet ( in this case) which also has a relationship with that same ad network (the relationship between sites and ad network gets complex but that’s beyond the scope of this post) i.e. this other site also has a JavaScript from that same ad network on their pages then that JavaScript(on a page on can read the previously set cookie to identify the visitor. By reading the cookie, the Ad Network knows who this visitors (computer) is (anonymously) and what sites this visitor (computer) was on, what products he looked at and if he abandoned the shopping cart or not and then serve up an appropriate retargeting ad.

Related Post
Behavioral Targeting 101

Purchase Retargeting course

Need help with Retargeting?  Contact me at


  1. Retargeting is one of the most effective forms of online advertising that is just starting to come into it's own. It's important to take careful note of the analytics associated with a retargeting campaign to make sure that you are getting a 360 degree view of your campaign.

  2. Thanks for this informative post! The exact definition of retaegeting is however not clear to me. According to wiki it is "based on previous Internet actions that did not in the past result in a conversion".

    However, this is also the case for behavioral targeting. First phase: you show the ad and collect data. Second phase (when the visitors come back): you show them the ads according to their behavior in the past (whatever the past is one day or one month).

    Maybe the "re" in retargeting highlight the idea that the ad can appear on a different web site.

    What do you think?


  3. Anonymous5:15 PM

    Even google is into behavioral targeting with adsense. I am sick of all this. I started using offshore VPN from for protecting my privacy. So far happy with the result. While on VPN and thinks I am from France and redirects me to FR site. If they cant track me I doubt other sites can.

  4. Anonymous1:22 PM

    So is 'Retargeting' effectively the same as what was discussed in the Behavioral Targeting 101 post calling the practice 'Network Targeting'?

  5. Excellent post. Retargeting can be a very effective way to bring recent visitors back to your site, potentially turning them into customers. It’s actually a marketing approach that’s been around for awhile, and with Google’s recent announcement of "Adwords Remarketing", it’s sure to quickly gain popularity.

  6. As said before, retargeting is an effective way of capturing lost sales and increasing brand awareness. I think networks matters greatly, good thing to look in to when looking for a supplier.


I would like to hear your comments and questions.