ReTargeter Blog

A Definitive Guide to Audience Extension

The relationships publishers have with their highly-valued audiences are no longer confined to only their websites. The improved technology surrounding the management and optimization of user data has given rise to audience extension, a service that is expanding digital boundaries for both publishers and advertisers alike. Audience extension helps transform a publisher’s traffic into an advertiser’s audience, enabling publishers to monetize their site visitors and advertisers to reach those visitors all over the web.

With 3 out of 4 digital publishers currently offering audience extension to their advertising partners, it is clear that this technology is gaining traction and providing attractive results to many players in the digital realm.

What is audience extension?

Audience extension is a technology that allows digital publishers to generate revenue from their web traffic by allowing advertisers to reach their audience far beyond their website. What’s appealing to many publishers about audience extension is that they don’t necessarily need to open inventory on their own site to use this service; they can choose to maintain an ad-free site while still monetizing their audience. Through audience extension, publishers can track their website visitors, and then advertisers can serve ads to that audience on different sites as they continue browsing the web.  Publishers can choose how much of their onsite inventory they want to open up for advertising if any. So, regardless of their own ad-serving practices, publishers can use audience extension to generate revenue by providing advertisers with the ability to track their unique audience and keep contacting them with advertisements across the web.

How does it work?

As is common with all behavioral advertising, audience extension relies on cookie-technology to track user’s browsing activity and detect what they might be interested in. Cookies are small text files that anonymously store data about the user’s browsing behavior, such as site visit history. All publishers have to do to begin extending ads to their audience is place a few lines of code in the HTML of their website, which tags people who visit their site with a special retargeting cookie. From that moment forward, this web audience will continue to see ads from any advertisers that publisher has provided access to as they continue to browse the web.

Audience extension technology allows advertisers to identify which audiences they hope to target the most based on the types of users visiting a particular site. In a way, it converts a publisher’s audience into a ready-made segment. Using a site’s audience as a segment can be valuable for tracking people who have demonstrated an interest in a certain topic, service, or geographical location. For example, an advertiser might decide they want to serve ads featuring the University of California, Berkeley to the audience of a popular college-reviews website. The college-reviews website can essentially sell its valuable audience to UC Berkeley for advertising purposes. Depending on the data the college-reviews website is collecting, it may even be able to specifically target its site visitors from California, thus allowing UC Berkeley to reach a highly relevant audience.

How is audience extension used?

Audience extension provides powerful solutions on both the buy and sell side of digital advertising.


With audience extension, advertisers can reach a specific audience that is of major interest to them, in greater numbers and with more frequency. If an advertiser is happy with the conversion rates or demographics of a particular publisher’s audience they can serve those users a higher quantity of ads across the web instead of flooding the publisher’s site with banner advertisements. Often, being inundated by the same messaging through the same channel results in banner blindness, the phenomenon by which people fail to notice objects that are right in front of them. Audience extension provides a solution to banner blindness because it allows advertisers to display ads on a variety of sites, thus creating new contextual associations in the mind of the viewer. In addition, advertisers should also make a point of rotating creative and A/B testing their ads regularly to further increase performance.

Another draw of audience extension for advertisers is the ability to target viewers of content-rich sites. Publishers have an unparalleled amounts of data on their own site visitors, specifically user interests and purchase intent. Advertisers can capitalize on this data and serve specialized ads to the most relevant people, increasing chances for conversions. Using highly optimized messaging, advertisers have a unique opportunity to reach in-market, targeted audiences via audience extension.


“Increasingly, advertisers are asking us for advanced targeting capabilities…not only can we scale to deliver more active moviegoers, we can further segment them based on specific behaviors and engagement patterns.”  –Megan Wigert, Vice President of Interactive Inventory at NCM Media Networks.

As Wigert expresses, advertisers want greater digital reach, and with this growing interest comes great opportunity for publishers. Whether or not publishers have on-site ad inventory, audience extension allows them to increase revenue by satisfying the growing demand for meaningful segmentation among audiences without relying on 3rd party data. Here at ReTargeter, we have access to over 98% of display inventory of the web, which means publishers using our services can help advertisers reach their audience virtually anywhere they go online. By investing in our audience extension service, publishers can generate revenue in an efficient and easy way they might not have known existed otherwise — without having to offer up more ad space.

The future of audience extension:

As advertisers continue to build digital strategies for reaching their client’s target markets in the most effective manner possible, publishers are starting to capitalize on just how valuable their audiences are through services like audience extension. This trend will surely continue to grow, granting advertisers access to the web via first-party data like never before.

The sophistication with which both digital buyers and sellers can use audience data has raised privacy concerns among many who worry their personal online-behavior is being commercialized and exploited. However, skeptics should know that while this technology may seem suspiciously good at delivering customized advertisements, nobody’s personally identifiable information is gathered or exchanged by publishers or advertisers when it comes to behavioral advertising. Strict regulations exist to ensure online privacy; therefore, not only would it be hugely inefficient for publishers and advertisers to spend time identifying and targeting individuals, it would destroy their businesses entirely.

Services like audience extension are helping to create a more and more personalized online experience, where your browsing experience is unique to your likes and dislikes, with advertisements that are more relevant, interesting, and useful. As audience extension continues to offer an innovative and lucrative solution for both publishers and advertisers alike, there is sure to be rapid expansion surrounding behavioral advertising of this kind.



Case Study – Watters

Watters Logo | ReTargeter

Watters is the brainchild of designer Vatana Watters. For over 30 years, it has been the leader in offering luxurious designer bridal gowns, innovative bridesmaids dresses, classic special occasion dresses for mothers of the wedding, and adorable dresses for flower girls and junior bridesmaids around the world. Selling primarily at trunk shows and in third-party […]

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