If there’s one area of Google Ads that often baffles even seasoned practitioners, it’s audience targeting.
Within audience targeting, there’s a special option called custom segments that allows us to build our own audiences using Google’s proprietary data. While custom segments can be immensely powerful, they are also immensely confusing.
What is a custom segment in Google Ads?
A custom segment lets you build a targeted audience based on the content a user has recently interacted with.
Think of it this way: instead of saying, “I want to show an ad on a website about running shoes,” you’re saying, “I want to show an ad to a person who has recently shown interest in running shoes.”
The way I like to explain it is that you are turning content targeting into audience targeting.
How to build a custom segment in Google Ads
You can build a custom segment from Audience Manager, or within the Audiences section of any compatible campaign. After naming your segment, you have the option to give it up to four different inputs:
- Interests: People with specific interests or purchase intentions.
- Search Terms: People who search for certain things on Google properties, like Google Search and YouTube.
- Websites: People who browse certain types of websites.
- Apps: People who use certain types of apps.
If you would like to use multiple inputs, I recommend creating multiple custom segments rather than lumping them all together. That way, you can see in your audience segments reporting if, for example, the “search terms” or “websites” perform better.
The best way to use custom segments in Google Ads
In my experience, the most useful type of custom segment is one based on search terms. Note that “your ads will reach people who search for those and similar terms” – so consider these to be Exact Match close variants rather than pure Exact Matches.
Here’s how to get started:
- Get your data: Go into your existing Search, Shopping, or PMax campaigns and pull the Search Terms report. Grab your top 20 to 30 non-branded search terms, either your best converting, or the ones you wish you were getting more impressions and clicks on
- Build the segment: Create a new custom segment and use those top 20-30 search terms as your only input, as “People who searched for any of these terms on Google”.
- Target in Demand Gen: Apply that custom segment to a new Demand Gen campaign, ensuring that optimized targeting is turned off.
Why Demand Gen?
Search term-based custom segments only work as intended on Google-owned properties.
If you use this segment in a Demand Gen or Video campaign, with Display network/Video partners turned off, then your ads are only serving on networks that Google owns (YouTube, Discover, Gmail, Maps), so Google knows who the user is and what they’ve recently searched for.
But if you try to apply the same segment to a Display campaign, which shows ads on millions of websites and apps that Google doesn’t own, Google won’t know who all of those users are, so it treats your “search terms” as “interests” instead.
You could still reach a relevant audience, but you lose that critical search intent that makes the search term segment so valuable.
Why is this the best strategy?
Same intent, low cost. By using a search term-based custom segment in Demand Gen, you’re reaching the exact same person you’re trying to reach in Search or Shopping, as they’re doing other things online.
For example, Google knows that they just searched for “best small business CRM.” Showing an ad on Google Ads would likely cost you $20+ per click. But now, they’re checking their email or scrolling their YouTube home feed.
You can show them an ad, and if they click, it will likely cost you closer to $1 per click. That’s like a 95% discount for the exact same user!
I prefer to execute this strategy in Demand Gen rather than YouTube campaigns because you can use click- or conversion-based bidding, and you don’t need video assets.
Website and App targeting: custom segments vs. placements
If you decide to build a custom segment using website URLs or apps, remember the important distinction here:
- You are not necessarily showing ads on those specific websites or in those specific apps (that would be placement targeting)
- You are not necessarily showing ads to people who have visited those exact websites or apps (only the owners of those websites or apps can do that via retargeting)
Instead, you’re showing ads to people who visit websites similar to those you listed, or people who use apps similar to those you listed. It’s a subtle but critical difference.
Don’t avoid this feature, but make sure you understand what you’re really doing (and not doing) before putting a big budget behind it. This is why I prefer search term-based custom segments, because I know exactly what I’m getting from an audience perspective.
Custom segment campaign compatibility & name changes
Shakespeare tells us, “That which we call a rose by any other name would smell as sweet.” Similarly, a custom segment by any other name still smells as sweet – but it does go by many different names! Here’s your cheat sheet:
- Demand Gen & Display campaigns: A custom segment can be built using interests, search terms, websites and/or apps. “Search terms” only works as intended in Demand Gen, not in Display
- Video campaigns: A custom segment can be built using interests, websites and/or apps, and it will be called a “custom interest” instead of a “custom segment.” To build a custom segment based on search terms, look for a targeting option called “custom search terms.”
- Performance Max: As with Video campaigns, a custom segment can be built using interests, websites and/or apps, and it will be called a “custom interest” instead of a “custom segment.” Remember that this is just an audience signal, not true audience targeting. Instead of a custom segment based on search terms, PMax offers the “search themes” signal option.
- Search & Shopping campaigns: Custom segments are not compatible with Search-based campaigns
Custom segments are a fantastic entry point for audience targeting in your Google Ads strategy, especially if you haven’t ventured outside of Search before. Start simple, use your search data to inform your targeting, and watch how that high-intent audience performs when you catch them in a different part of their day.
This article is part of our ongoing Search Engine Land series, Everything you need to know about Google Ads in less than 3 minutes. In each edition, Jyll highlights a different Google Ads feature, and what you need to know to get the best results from it – all in a quick 3-minute read.