Retargeting
Retargeting explained
can support a purchase decision already in progress: an ad recalls a viewed product or answers an unresolved question. A visit without a purchase is not always a lost customer. Some people return on their own; others have deliberately decided against an offer. These differences matter for the message, budget and measurement.
Common approaches include reaching previous website visitors, dynamic ads featuring viewed products and ads following an abandoned cart. Interactions within an advertising platform may also support audience creation, depending on its features. Customer Match matches eligible customer data to accounts on an advertising platform. An audience of new people with inferred interests is not, by contrast, a repeat contact with previous visitors.
A useful plan defines the relevant behaviour, time since the interaction, suitable content and exclusions. After a recorded purchase, the original purchase prompt should be reviewed or excluded. Contact frequency and campaign duration depend on the decision cycle, product and audience response. There is no universally appropriate number of ads per day. Tracking and cross-platform frequency controls also have limitations.
A high retargeting conversion rate does not establish an equally large advertising effect. The people reached already had an interest. The key question is which additional purchases or qualified enquiries the advertising causes. Suitable control groups or conversion lift tests can examine this contribution when enough data and the necessary platform features are available. Evaluation should include costs, margin, the comparison period and uncertainty in the result.
Before deployment, establish the legal basis, required consent, transparent information and applicable platform rules. An existing customer relationship or simply providing an email address does not automatically authorise its use for advertising matches. First-party data and server-side processing do not, by themselves, demonstrate compliance. Withdrawals of consent and deletion requests must be accounted for in the relevant process.
AI can assist with tasks such as ad variants and delivery decisions. Whether this produces better communication and an economic benefit must be measured against the specific objective. Relevant messages, suitable landing pages and additional outcomes are the criteria. The following scenarios illustrate possible applications, subject to the necessary data-use and consent requirements.
Examples
Illustrative scenario: online shop
A fictional shop could show an ad for a viewed product to people who abandoned their cart. Availability and price would need to be current, with already recorded purchases excluded from this message.
Illustrative scenario: B2B information
A provider could invite previous visitors to a product page to a more detailed . Evaluation would cover additional qualified registrations and subsequent sales quality.
Illustrative scenario: longer purchase decision
A fictional furniture brand could follow a product view with material information instead of an immediate discount. A test would assess whether this support generates additional qualified enquiries.
Illustrative scenario: complementary offer
A service provider could show suitable existing customers a complementary offer where the data may be used for that purpose. A comparison group would help distinguish additional sales from purchases that would have happened anyway.
Key Points
- Retargeting builds on a previous interaction.
- Match the message, timing and exclusions to the situation.
- Monitor contact frequency and set appropriate limits.
- High conversion rates do not establish additional sales.
- Where feasible, evaluate results with a suitable control comparison.
- Customer data and server-side processing do not replace legal assessment.
Sources and context
- Google Ads: About Conversion Lift
Explanation of measuring additional conversions with test and control groups.
- Google: Customer Match policy
Requirements for collecting, sharing and using customer data for Customer Match.
- EDPB: Guidelines 8/2020 on targeting social media users (PDF)
Guidance on responsibilities, legal bases and transparency in social media targeting.
Frequently Asked Questions about Retargeting
Retargeting uses digital ads to reach people again based on a previous interaction, such as a website visit or product view. Which data may be used and which audiences can be reached depend on the specific implementation.
Examples include previous website visitors, people who viewed products or people who interacted within a platform. Permitted data use, available platform features and the relevance of another contact determine suitability.
No. The people reached already had an interest and might purchase without an ad. Suitable control groups or conversion lift tests help examine the additional contribution of the advertising.
No. Collecting an email address or having a customer relationship does not automatically authorise an advertising match. The legal basis, required consent, transparent information and platform rules must be established for the use. This also applies to server-side processing.
There is no universal number per day. Contact frequency and duration depend on the product, decision cycle and audience response. Recorded purchases and other reasons for exclusion should be considered.
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