Remarketing is the most commonly discussed tactic in ecommerce advertising and one of the most misconfigured. Store owners create an audience list, attach it to a campaign, see 0 users, and conclude remarketing does not work. Usually the problem is not the strategy — it is the setup.
Here is how Google Ads remarketing actually works and how to build a setup that functions.
How Remarketing Lists Are Built
A remarketing list is an audience of users who have previously visited your site or taken a specific action. Google builds these lists by tracking users across sessions using cookies, advertising IDs, and (with Enhanced Conversions) hashed email addresses.
There are two places to create remarketing lists for Google Ads:
Directly in Google Ads (Google Ads tag-based lists): using the Google Ads tag (gtag.js) on your site, you can create lists based on URL visits, events, and tag parameters. These lists live in Google Ads Audience Manager.
In GA4 (GA4 audience export): you build audiences in GA4 using GA4’s event and parameter data, then publish them to your linked Google Ads account. These appear in Google Ads as imported audiences.
Both methods work. GA4 audiences are more powerful because GA4 has richer behavioural data — you can build audiences based on complex event sequences, parameter values, and predictive signals that the Google Ads tag alone cannot match.
The Most Common Setup Mistake: Minimum List Sizes
Google Ads requires a minimum audience size before a remarketing list can be used for targeting:
- Search and Shopping (RLSA): 1,000 active visitors in the last 30 days
- Display: 100 active visitors
- YouTube: 1,000 active visitors
If your audience list shows 0 users or a size below the minimum, the list cannot be used for targeting — it will appear in your campaign but will never actually influence bid decisions or ad delivery.
New stores and low-traffic stores frequently hit this wall. A Shopify store with 300 monthly sessions cannot build a 1,000-user remarketing list for Search regardless of how correctly the setup is configured. For these stores, Customer Match lists (built from email addresses, not site visits) are a more practical starting point — they require a minimum of 1,000 matched users but can be built from existing customer emails rather than requiring current traffic.
Building the Right Audience Tiers
The value of remarketing comes from differentiating between users at different stages of purchase intent. Not all site visitors are equally valuable to retarget.
A practical tier structure for ecommerce:
Tier 1 — Cart Abandoners (highest intent)
Users who added a product to their cart but did not complete the purchase. This audience converts at the highest rate of any remarketing segment. The intent signal is explicit — they wanted to buy and something stopped them.
In GA4: create an audience with event condition add_to_cart AND NOT purchase. Set a lookback window of 30 days.
In Google Ads audience manager: create a website visitors list with URL condition “contains /cart” and exclude URL “contains /checkout/thank-you” (or your equivalent order confirmation URL).
Tier 2 — Product Page Viewers (high intent)
Users who viewed specific product pages but did not add to cart. These users showed product-level interest but did not reach the add-to-cart decision.
In GA4: create an audience with event view_item AND NOT add_to_cart.
In Google Ads: create a list with URL containing your product URL pattern (e.g., /products/) and exclude users in the cart abandoner list.
Tier 3 — General Site Visitors (lower intent)
All users who visited the site within a lookback period, excluding purchasers. This is the broadest audience — useful for upper-funnel retargeting at lower bids.
Tier 4 — Past Purchasers (exclusion and LTV targeting)
Users who have completed a purchase. Use this list for two purposes: exclude from prospecting campaigns (to avoid spending acquisition budget on existing customers) and target with repeat purchase or cross-sell campaigns.
RLSA in Shopping Campaigns
RLSA (Remarketing Lists for Search Ads) in Shopping campaigns works differently from standard audience targeting. In Shopping, you cannot show ads only to remarketing list members — there are no keywords to match against. RLSA in Shopping operates as a bid modifier.
You attach a remarketing list to a Shopping campaign or ad group and set a bid adjustment: for example, +40% for cart abandoners. This tells Google to bid 40% more aggressively when the search comes from a user on that list.
The impact: your products rank higher and appear more frequently in Shopping results for users who have already shown interest. Your budget is still spent on all eligible searches, but you compete more aggressively for the high-intent subset.
To set this up: in your Standard Shopping campaign, go to Audiences. Add the audience list and set the bid adjustment. For PMax campaigns, audience signals serve a similar but less directly controllable purpose — add your remarketing lists as signals, which directs PMax’s optimization toward users who resemble your past visitors.
How to Create Remarketing Audiences in GA4 for Google Ads
In GA4, go to Configure, Audiences and click New Audience.
For a cart abandoner audience:
- Add condition: Event name equals
add_to_cart(included) - Add condition: Event name equals
purchase(excluded) - Set membership duration to 30 days
For a product page viewer audience:
- Add condition: Event name equals
view_item(included) - Add condition: Event name equals
add_to_cart(excluded) - Set membership duration to 14 days
After creating the audience, it will appear in the Publishing section. Enable publishing to your linked Google Ads account.
It takes 24-48 hours for audiences to begin populating in Google Ads after they are published. New audiences start at 0 users and grow as matching users visit your site. For cart abandoner audiences, you will reach a meaningful size faster than for lower-engagement audiences.
The audience size check: after 48 hours, go to Google Ads Audience Manager and check whether the audience shows a user count. If it shows ”< 1,000” or a specific number below the minimum threshold, the list is not yet usable for Search or Shopping RLSA. Continue waiting and monitor growth. A store with 5,000 monthly sessions should reach 1,000 remarketing list size in cart abandoners within 1-3 weeks depending on add-to-cart rate.
Why Your Remarketing Audience Shows 0 Users
If an audience shows 0 users after more than 48 hours, the possible causes are:
GA4 is not tracking the relevant events. If add_to_cart events are not firing in GA4, the cart abandoner audience will never populate. Verify in GA4 DebugView or the Events report that the event is being received.
The GA4 property is not linked to Google Ads. Audiences only export to linked accounts. In GA4, go to Admin, Product Links, Google Ads Links and verify the link is active.
The audience condition is too restrictive. An audience with five conditions that all need to be true simultaneously may match almost no users. Simplify the conditions and check whether the audience starts populating.
Consent mode is blocking cookie-based audience building. If a large portion of your users decline consent, they are excluded from cookie-based audience tracking. Your effective audience pool is smaller than your total traffic. This is expected behavior and the correct response is Enhanced Conversions plus Customer Match for coverage beyond cookie-based tracking.
Display Remarketing vs. Search Remarketing
These serve different purposes and should be evaluated separately.
Search remarketing (RLSA) shows ads to people already searching for products. The intent is already there — you are just bidding more aggressively for users who are more likely to buy from you specifically. This is highly efficient because you are only spending more on searches that already have purchase intent.
Display remarketing shows banner ads to past visitors as they browse other sites. There is no active search intent — you are keeping your brand visible and nudging users who have not yet purchased. Display remarketing conversion rates are lower than RLSA because the context is passive browsing rather than active search.
Evaluate them with different benchmarks. A 200% ROAS from display remarketing and a 500% ROAS from RLSA are both potentially valid depending on your category and margins. Comparing them directly and cutting display because it “performs worse” ignores that they operate in fundamentally different contexts.
Frequency Caps for Display Remarketing
Without frequency limits, display remarketing can show the same person the same ad dozens of times in a day — which irritates users and wastes budget.
For Display campaigns, set an impression frequency cap at the campaign level. A reasonable starting point is 3-5 impressions per user per day, 10-15 per week. This maintains brand visibility without overexposure.
Google Ads Display campaigns have frequency settings under Campaign Settings. In Performance Max, frequency is managed automatically by Google’s delivery system, with limited manual control.
The Exclusion That Most Stores Skip
Always exclude your past purchasers from prospecting campaigns. This is one of the highest-value applications of remarketing lists, and most stores do not do it.
A user who bought from you last month is not a new customer acquisition target. Spending acquisition budget to bring them back is re-engagement, not prospecting — and re-engagement is typically cheaper through email or Customer Match targeting than through prospecting campaign bids.
Add your purchaser list as an exclusion audience to every prospecting campaign. This keeps prospecting budget focused on users who have never bought from you, which is where the real customer acquisition value is.
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