How to Use Custom Affinity Audiences for More Cost-Effective Google Display Ads

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Last Updated: October 16, 2022 | Display Ads
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If you didn’t already know, the Google Display Network (GDN) is a platform advertisers can leverage to reach over 90% of global internet users, expanding across more than two million websites.

But it’s far more complicated than it first seems. There are so many factors that contribute to the success of any display campaign – not the least of which is what part of that huge potential audiences you decide to target.

In this article, I will be discussing ways for you to leverage Custom Affinity Audiences in order to run more efficient advertising campaigns across the Google Display Network.


If you’ve browsed around the Google Ads interface, you may well have seen this option – it’s buried somewhere in the Audiences tab. More specifically, it pops up when you select “What their interests and habits are.”

There are tons of different methods that allow you to define the audience that your banner ads will reach, and Google does a great job of working with their data to allow you to select predefined audiences that are based on their interests, habits, searching patterns, and interactions with your site. But quite often you’ll find these audiences far too broad.

What Are Affinity Audiences?

Firstly, let’s quickly define what “Affinity Audiences” are in Google Ads audience targeting, before we dive into the world of custom. You can think of affinity audiences as similar to TV audiences – wildly generalized types of people that watch your varying TV channels. So BBC One would represent (kind of) older demographics, people interested in politics and news, whereas E4 would represent your younger demographics (I guess), perhaps those chilling around in their university dorms… you get the idea. Although there is some truth in this system of categorization, it is very broad and presumptuous.


Google accomplishes something similar by piecing together acquirable information from a particular user – the pages they frequently visit, the time they spend on different sites, their search patterns, etc. The outcome is a list of predetermined audiences organized by affinity, or predisposition toward, such as “Sports Fans,” “Food & Dining,” and “Travel.” But remember, these are large TV-style audiences. It’s not a perfect science.

This is where custom affinity audiences really show their worth: the ability to define your very own audience, allowing you more control over who sees your ads (and we love control and transparency).

What Are Custom Affinity Audiences?

Note: Custom intent and custom affinity audiences have merged and are now simply called custom audiences.

The criteria for setting up a custom affinity audience or CAA is to think of a minimum of five different interests, URLs, places, or apps that best define the audience that you are trying to target.

Now in my experience, places and apps aren’t particularly useful, and they also limit your reach. You can target your perfect niche audience just through URLs and interests.

Setting these up are really easy: find the audiences tab within an ad group of your choice, click the “What their interests and habits are” section, and you’ll see towards the bottom that there is an option to create a Custom Affinity Audience. It will ask you what you want to name your audience, and you can choose to give it a pleasant description if you fancy. I’ve gone ahead and pretended that I want to target Protein Bar Lovers.


I’ve used a combination of five interests (entered as keywords) and two URLs. For specificity, it’s far better to select specific page URLs rather than a website’s domain or homepage.

What happens in the background here is that Google will analyse the URLs I’ve provided to get a good idea of the audience I’m after from the contents of those pages. If we were to target “” as a whole, my audience would change massively – from users who are specifically interested in protein bars to users interested in supplements, sports clothing, workout plans, etc.

Now that wouldn’t be cost-effective advertising if my imaginary business only sold protein bars…

When to Use Custom Affinity Audiences

Do any of the initiatives below describe your advertising goals?

Considering the very nature of the way we set CAAs up, they are practical for so many different businesses and situations. There are literally millions of different ways we can reach relevant audiences, simply by playing around with different items (interests, URLs, places, apps).

Even if you’re a brand new business selling tennis racquets, although the market place is inevitably going to be enormous and fiercely competitive, you can still think of strategic ways to target relevant users, and raise your brand awareness while making sure it’s highly cost-effective.

Strategies for Making the Most of Custom Affinity Audiences

Hopefully, now that you understand Custom Affinity Audiences better, you’re inspired to give it a go. Now I’ll share with you a couple of ways that I’ve used CAAs to target relevant audiences.

Top Performing Placements

If you have ever run reasonable amounts of display activity, or if you currently are, then pull out a “Where ads showed” report. You’ll want to sort your placements by your chosen measurement metric (such as “Conv. Rate,” “Avg. session duration” etc.) and analyze which ones perform the best, but make sure you have enough data to make this analysis reliable. You don’t want to choose a supposedly excellent placement if it’s based on two clicks.

Get your top 10 placements, and place them into a Custom Affinity Audience. Et voila! Strategy one complete.

The theory here is that for some reason, users who are advertised to on certain placements resonate with your business better than others. By selecting these into a CAA, we’re prompting Google to analyze these placements, defining the audience that engages with your business from those placements, and to go on and find users on the world wide web that fit the bill.


The picture above is a quick export of some placement data. My measurement metric is Conv. Rate (on the far right hand side). I can quickly gather which placement URLs perform well, and put them into my CAA.

Competitor Targeting

Custom Affinity Audiences offer a fantastic way to reach your competition’s audience. By using a competitor’s site or specific pages on their site as URL targets and entering their brand keywords as interests, you can efficiently target relevant users on the GDN.

Depending on who your competitors are, simply doing the above will be enough. But in some cases you’ll need to manage this targeting more closely. If your competitors are enormous, then you’ll want to target page-specific URLs, and you’ll probably want to create a singular campaign for that competitor CAA, to be able to better manage the budget and spend.

Alternatively, you might be targeting your small competitors in a local region. In which case, throw your competitor’s domain into the URL section, and expand on the interest items a bit more – include the services or products you are competing on, as well as their brand.


Here’s what you might do if you were a local massage clinic, offering physio and sports massages.

Event Attendees

Another great way to reach relevant users is by targeting trade shows, conventions and conferences. The people that attend these events are likely to be more engaged with your products or services over anybody else. These people literally pay to attend these types of events, so you’d think they’d be interested in the said product or service.

I’ll use SMX London as an example: a conference run each year which promotes the latest updates in the digital marketing world. If my target audience was digital marketing fanatics, then I’ve found a jackpot audience.

I’ll take the most relevant URL “”, key in various interests such as “digital marketing,” “search marketing,” “SEO,” “PPC,” and there we go – Google should now understand the audience we’re defining and will target your ads to them.


User Behavior

In the scenario of owning a tennis racquet business, targeting interests such as “improve tennis serve,” “forehand tennis tips,” “tennis practice” may pay dividends.

Here’s why. This target audience will give us a better shot of getting in front of a more active user than just targeting “tennis enthusiasts” (an example of a predefined Affinity Audience). Users who are looking to improve their tennis don’t just watch it, they play tennis, with racquets. At least we know we have a better chance going with this route, as opposed to the basic affinity audience.

By narrowing audience segments by behavior, you are able to target users lower down the conversion funnel.The funnel metaphor is used because there are loads of people at the top of the funnel who are remotely connected with the sport of tennis, but as we improve our targeting – yes, the volume of prospects drops, but the likelihood of converting a prospect into business increases. Making sure we target the lower funnel is cost-effective!


Custom Affinity Audiences: A Mini Case Study

I thought I’d share with you a quick preview of the results I have achieved for a client of mine, who works in the legal industry. The legal sector is one of the most expensive to advertise in, with the average CPC for this client hitting £8.11 (“All Time” data). I was convinced we could target relevant audiences through display advertising at a tiny fraction of the CPC.

So, naturally, I turned to Custom Affinity Audiences, defining my custom audience by thinking about what prospects might search to get the legal advice my client offered. I married keyword interests with websites that prospects would browse through – websites that offered advice, compared legal firms, and also included some of my client’s competitor websites.

The results were remarkable! Concluding the first six weeks of launching the display campaign, we had managed to acquire conversions at 18.77% of the price compared to search. Let me share with you the stats below:


This six-week trial period proved just how successful display could be for this particular lead gen client.

Key Learnings

Custom Affinity Audiences allow for more control on the GDN. They perform best as a creative way to reach new users in a cost-effective way, and help to drive incremental conversions. The benefits of CAAs are clear:

  • More controlled targeting via GDN
  • Excellent for reaching new audiences
  • Ability to target a very relevant audience
  • Help drive conversions
  • Highly cost-effective

About the Author

Leo Worsley is a Paid Media Specialist at Hallam, who has a passion for working with data insight. When he isn’t developing mathematical models for his accounts, you might see him kicking around in snooker clubs or at the gym. Find him on LinkedIn.

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