When a customer buys your product because of an ad they saw, something went right. Your shop was in the right place at the right time. Or, in 21st-century terms, your shop was on the right device at the right time.
There’s just one problem with replicating this success: What if there are multiple right places to find your customers? Multiple right times?
Welcome to the world of cross-device ad targeting.
According to Think With Google, it’s not often accurate to think of customers as strictly offline or online. Customers most often use multiple channels before buying. For an average purchase, a customer may use several touchpoints across multiple channels.
That leaves us with one question: How can you create a consistent advertising experience for customers when those customers aren’t taking one road to the purchase? You can find the answer in cross-device ad targeting.
What is cross-device ad targeting?
Cross-device ad targeting recognizes one person behind multiple screens and serves a coordinated ad sequence to that individual, not each device separately.
The average global consumer already juggles 3.6 devices, and in the US, the average person owned 13 connected devices as of 2023. And the shopping experience happens on so many surfaces:
- Desktops and laptops
- Connected TVs and streaming ads
- Mobile web
- In-podcast ads
- In-app mobile, such as social media ads
- Email newsletters
- Smart speaker ads
Imagine a shopper who checks Instagram on her phone at breakfast, researches reviews on a work laptop, watches YouTube on a smart TV after dinner, and finally completes the purchase from a tablet on the couch.
With cross-device targeting, you can:
- Cap impressions at the person level to avoid fatigue.
- Tell a story (from awareness to consideration to offer) no matter which screen they are on.
- Attribute every touch to the final sale for a true view of your return on ad spend (ROAS).
We know the trends are pointing toward customers using multiple various devices. The question is, does that translate to success when brands use cross-device ad targeting?
L'AMARUE used Shopify Audiences to find new buyers within weeks after experiencing a sharp decline in accurate audience targeting. It helped them navigate the shift in digital media, resulting in a 48% uptick in click-through rate and a 2.5x return on ad spend.
Tracking in cross-device targeting
Shoppers will bounce from phone to laptop and beyond. To deliver a fluent ad journey, you have to know it's the same person behind every screen. This is called identity resolution, and it happens through two methods:
- Deterministic tracking: When you match signals with unique characteristics for an individual, like email addresses, loyalty card numbers, OAuth logins, and other first-party data. These identifiers come from the user, and their accuracy is nearly 100%.
- Probabilistic tracking: When a machine learning model infers that two devices belong to the same person based on IP address, device type, and browser plugins. It helps fill the gap for users who browse anonymously.
A modern ad approach combines these two to create a hybrid graph. Solutions like Shopify do exactly this by helping you build unified customer profiles and target lookalike users through Shopify Audiences.
Google’s on-again, off-again plan to retire third-party cookies in Chrome (most recently paused in 2025) means marketers can’t rely on cookies alone. The way forward uses deterministic first-party IDs (like Shopify’s unified profiles), then layers in a reputable identity-graph partner to extend reach.
Device graph vs. identity graph
Deterministic and probabilistic signals are only half the story. How you stitch them together decides whether you deliver a precise, personalized ad, or a generalized device-level one. It comes down to whether the framework you use is a legacy device graph or a modern identity graph.
Think of the difference like a Scooby-Doo episode. A device graph follows scattered footprints, while an identity graph yanks off the mask and reveals it's the same villain—or shopper—every time.
| Device graph | Identity graph | |
|---|---|---|
| Primary signals | Third-party cookies, mobile ad IDs, device fingerprints | Deterministic IDs (hashed email, Shopify customer ID, loyalty #) |
| Resolution level | Device-level (ties actions to a browser or handset) | Person / household-level (all devices mapped to one human) |
| Accuracy | Less accurate as browsers block key IDs | Highly accurate |
| Best uses | Basic retargeting, device-level frequency capping | Sequential storytelling, omnichannel attribution, personalized offers |
| Future potential | Shrinking as cookie pools dry up | Thriving as it's built on first-party data |
Why the device graph is fading
Device graphs were designed for a cookie-centric internet. As browsers block third-party cookies, the match quality becomes worse. Google’s latest reversal left cookies active, but under user-choice controls, none of which restores lost signal quality.
Why the identity graph wins
Identity graphs cluster every deterministic ID you already have in your customer profiles, and widen reach with privacy-safe lookalike devices. One email at checkout, a Shop Pay tap in-store, or a newsletter signup instantly updates a first-party profile you own.
Kate Hewko upgraded to Shopify Plus to leverage Shopify Audiences' ability to find new customers and eliminate guesswork in ad attribution. During a three-week campaign, Shopify Audiences outperformed other audiences significantly, achieving a 45% higher ROAS and 8% lower cost per acquisition.
How to do cross-device ad targeting
1. Map the customer journey
List out every paid, owned, and earned touchpoint where shoppers appear. It could be a Google Shopping ad, QR code in-store, post-purchase email, loyalty program, etc.
Shopify’s unified data model makes it easy to collect and house this information in a centralized operating system. Inventory, order, and customer data flow back to the same dashboard, no matter where you sell, to give a complete 360-degree view of your customer.
Turn every high-intent touchpoint into an ID event. For example:
- Encourage Shop Pay login or customer account sign-in.
- Prompt for email and phone number at your POS.
- Embed opt-in forms on your website.
You can also add customer tags that use programmatic automations to trigger after a specific action or a defined event, like a customer signing up to your shop. This creates specific user IDs. Used in conjunction with unique landing pages for different devices, you can gauge your conversion rates on each.
If you’re using Shopify analytics, apply multiple levels of filters to get more specific views of your customers. It’s more of an art than a science, but it will help you better understand the full customer experience, and where they’re coming from.
2. Recognize user devices
Use an identity solution to collect public IDs that ad platforms already read. This will help you recognize a phone, laptop, or TV the minute it requests an ad.
Some examples include:
- Universal IDs (UID2, RampID)
- Mobile ad IDs (MAIDs)
- CTV or smart TV logins
- Third-party cookies
3. Merge the two sets of data in an identity graph
Upload your first-party data to a trusted graph partner like OnAudience, LiveRamp, or The Trade Desk. The company can link each persona’s private ID from Step 1 to the device IDs in Step 2, giving you one record that says “this person equals these seven screens.”
4. Push the list to your ad tech stack
Export the matched audience to your DSP, social network, or CTV partner. Now, you can run sequenced creative from TV to mobile to desktop, and attribute the final sale back to every touch in Shopify.
The advantages of cross-device ad targeting
Cross-device ad targeting engages people the way people engage with the world—through multiple connected devices. But how does it specifically offer advantages over more conventional, single-device strategies?
Higher engagement
One reason to employ cross-device marketing is that consumers, including millennials, already work this way. According to Aimee Blakemore, marketing manager at Flourish, “Conversion rates from users who have used multiple devices before landing on the website are 230% higher compared to average.”
From a customer’s perspective, ad engagement across multiple devices should be a seamless experience. They might learn about a product on social media as they browse their phone. Then they save the ad to an app, browse it later, and sign up for an email newsletter for the discount.
Later, when surfing on a laptop at a coffee shop, maybe they have the free time to use the discount code and make the purchase.
Market timing
Getting a customer to think about a purchase might work well at a specific time of day—when a customer is more likely to have their wallet out. If a customer is on mobile at that point of the day instead of desktop, a single-device ad campaign won’t cut it.
A cross-device ad targeting campaign can help businesses learn what the ideal timing is in the first place. For example, if you discover that mobile ads are ideal for top-of-funnel actions like subscribing to a newsletter, but not for conversions, that can help you in future campaigns. Ditto if you discover that newsletter coupon codes generate higher conversions than your desktop ads.
Tracking ad spend and ROAS
Big companies are cracking down on third-party cookie tracking. Rather than planting cookies in ads to follow customers across the web, ecommerce marketers will have to think more about the first-party data points they gather from direct analytics. Cross-device ad targeting casts a wider net for your data, showing you which devices are driving high engagement, without the use of cookies.
ROAS, or return on ad spend, is equivalent to return on investment (ROI) for your marketing dollar. Using cross-device tracking to measure this core metric helps you gauge which channels are most profitable.
There’s one caveat: you can’t identify the best devices for ROAS until you have a handle on your analytics. And to know what channels are converting and not converting, you need to have accurate multichannel attribution in place.
The good news is that once you do, it shouldn’t be long until you can figure out which ads on which devices are your top performers.
Examples of cross-device ad targeting
It’s one thing to talk about cross-device ad targeting, but what does it look like in practice? Below, we’ve explored some of the brands already using cross-device marketing to target their potential customers.
Red Dress Boutique
When Red Dress Boutique attempted a replatforming from Magento to Shopify, there was a lot of testing to be done. One of the most surprising results of these tests was finding just how much of the shop didn’t work across multiple devices.
Before advertising on multiple devices, Red Dress Boutique had to address these issues. For instance, the menu wasn’t working for certain devices and browsers. And the boutique had to finally add a View Cart button for their desktop “Shop the Look” feature.
The results were cross-device success. Red Dress Boutique exists online, in person, and on social media influencers’ pages. And during the replatforming to Shopify, they used the opportunity to address any holes in their cross-device strategies.
Emma Bridgewater
It’s not that the Emma Bridgwater story is that unique—the brand had an antiquated platform, and decided to add mobile ads and capabilities into the mix. But it was what Emma Bridgewater did behind the scenes that made their transformation remarkable.
It wasn’t just advertising: Emma Bridgewater built a new platform from top down, ensuring their images looked fresh on mobile and that they could sell in four major currencies, and updated their checkout processes for customers who wanted to finish an order on their smartphones.
The results were a 32% increase in mobile users and a 13% increase in mobile revenue after the update.
Making cross-device ad targeting work
For the customer, a cross-device ad targeting strategy is almost invisible. Behind the scenes, it takes some strategizing to make it work. But the result is always the same: reeling in more customers and creating a consistent brand experience that keeps people visiting.
Cross-device advertising FAQ
What is cross-device advertising?
Cross-device advertising is marketing aimed at creating a consistent message out to customers, no matter what device they’re using. The goal is typically to engage customers at multiple touchpoints, consistent with an omnichannel strategy, and drive customers to your ecommerce store. The approach can pay dividends in yielding new customer data and insights, and improving return on ad spend (ROAS).
Why do I need cross-device advertising?
Shoppers are increasingly cross-device customers. With desktop computers, smart speakers, TV sets, and streaming services in the mix, people are exposed to all sorts of digital advertising. Cross-device advertising builds consistency with customers across devices—or targets specific ones that best suit your marketing budget.
What are the advantages of cross-device advertising?
It drives high engagement, reaches more of your target audience, and gives you access to data about where and when customers convert. This enables you to better understand your core customers and optimize your marketing strategies.
What are the key obstacles to overcome in cross-device advertising?
Understanding context across devices, managing deterministic vs. probabilistic data, and avoiding ad fatigue from repetition are major challenges. Missteps can lower ROAS. However, with thoughtful targeting—like cart abandonment alerts—cross-device strategies can be highly effective.
What if my current ad targeting is already working?
If it’s working, keep going! But remain flexible—what works today may not tomorrow. Cross-device targeting is a low-risk exploratory strategy to test new channels and discover the best combination to drive conversions.
