Remarketing: Showing Ads to Past Visitors and Customers

What remarketing is

Remarketing (also called retargeting) means building an audience from people who have already interacted with your business and showing ads to that audience. The interaction might be a visit to your website, a video view, a lead form or a purchase recorded in your customer list.

The names have changed. Google's article About your data segments explains that "remarketing" is now referred to as "your data" in Google Ads. Its list of sources includes website visitors, people who used your app, people who interacted with your YouTube videos or channel, people who submitted a lead form in Google Ads, and customer lists through Customer Match. Meta calls the same idea custom audiences, built "from their own data sources or Meta engagement data".

Remarketing builds on tracking you may already have. The Google tag or the Meta Pixel records visits; our guides to Google Ads basics and Facebook and Instagram ads cover setting up the accounts and tags.

Website visitors in Google Ads

Google's help page on creating a website visitors segment walks through it. In Audience manager you add a Website visitors segment and set rules: which pages or events count, and how many days a visitor stays in the segment. You can pre-fill the segment with visitors from the previous 30 days if your site already has the Google tag, or start empty.

Rules can be broad (anyone who visited) or specific. Google's own example is people "who added something to their shopping cart but didn't complete a transaction". For a service business, the equivalent might be people who viewed a service page or the contact page but did not send an enquiry.

A segment needs enough people before ads can run. Google's Audience manager article says data segments for the Display Network, the Search Network and YouTube need a minimum of 100 active visitors or users within the last 30 days. A small site may take time to reach that.

One setting surprises people. With optimized targeting, including Performance Max, Google says your audience selections become signals, and "your ads may serve to them, even if they're not specified by your audience selections". If you want ads shown only to your segment, check the campaign's targeting setting.

Customer lists in Google Ads: Customer Match

Customer Match lets you upload contact details your customers have given you. When those people are signed in to Google, you can reach them on Search, the Shopping tab, YouTube, Gmail and Display. The Customer Match policy sets the conditions:

• Account history. Your account must have a good history of policy compliance and a good payment history.
• Targeting needs more. All policy-compliant accounts can use Customer Match lists for observation and exclusions. Using them in the "Targeting" setting, and for manual bid adjustments, needs 90 days of Google Ads history and more than USD $50,000 total lifetime spend.
• First-party data only. You may only upload information collected in a first-party context, such as purchases on your website, app sign-ups or a loyalty programme in your store. Bought lists are out.
• Disclosure and consent. Your privacy policy must disclose that you share customer data with third parties to perform services on your behalf, and you must obtain consent for that sharing where required by law or Google's policies.
• No children. You may not upload information about customers under 13 or collected from sites or apps directed to children under 13.
• Keep it fresh. List memberships expire after 540 days, and a list needs at least 100 members added or updated in that window to stay eligible.

The policy also bars ads that imply knowledge of personal or sensitive information about your customers, and lists aimed at an overly narrow audience. For a smaller account, the most useful option is often exclusion: leave existing customers out of ads meant to win new ones.

Custom audiences on Facebook and Instagram

Meta's custom audiences overview lists audiences from your own sources (website, app, catalog, customer list and offline activity) and from engagement on Meta's platforms: video views, lead forms, Instagram and Facebook Page interactions, events and more. An ad account can have up to 500 custom audiences, and any of them can be the source for a lookalike audience of similar people.

A website custom audience needs an active Meta Pixel. You choose the events or pages, set audience retention in days, and can add up to five rules. Meta notes that the audience "starts populating from the time you create it (ie, it won't backfill)", so create the audiences you expect to need early.

A customer list custom audience matches uploaded emails or phone numbers to people on Meta's platforms. Meta says the information is hashed before it is used for matching, and that under the GDPR the advertiser acts as the data controller for any list uploaded. Its Customer List Custom Audiences Terms require you to have a lawful basis for the data, to keep out data on children under 13 and sensitive categories such as health or financial information, and to remove people who have opted out. Meta marks a list as Outdated when it has not been updated in over 30 days, which may affect delivery.

Consent comes first

For visitors in the European Economic Area, the UK and Switzerland, Google's EU user consent policy requires legally valid consent for cookies where legally required and for "the collection, sharing, and use of personal data for personalization of ads". You must keep records of consent and tell people how to withdraw it.

Google's page on consent mode for EEA traffic says that to keep using tags for measurement, ad personalization and remarketing, you must collect consent from users in the EEA and pass the consent signals to Google. Consent mode has two settings for this: ad_user_data and ad_personalization. If a visitor declines, they should not join your remarketing audiences.

Meta's help pages note that changes made to align with European privacy rules may affect campaigns aimed at people in Europe. In practice, remarketing depends on a consent banner that works properly and passes the visitor's choice to each tag. Our guide to cookie consent banners covers that setup, and your privacy policy should say that you use advertising cookies and customer lists.

What you may not target

Google's personalized advertising policy lists sensitive interest categories, including health, religious beliefs, negative financial status, relationship hardships and race and ethnicity, with targeting restrictions. A clinic or debt adviser, for example, should check these before building audiences from page visits. The same policy forbids sending personally identifiable information, such as names or email addresses, to Google through your data segment tags.

In the United States and Canada, ads for housing, employment and consumer finance are in "access to opportunities" categories, where Google does not allow targeting by gender, age, parental status, marital status or ZIP code. Meta has similar limits for its special ad categories, covered in our Meta ads guide.

Using remarketing well

• Separate audiences by intent. Someone who read a pricing or contact page is closer to buying than someone who read one blog post. Give them different messages.
• Exclude people who already converted. Use a segment of enquiries or purchases, or a customer list, as an exclusion so you stop paying to show the same offer to customers.
• Match the time window to the decision. A takeaway order and a kitchen renovation have very different buying cycles. Set membership durations to suit.
• Give a reason to come back. Repeating the same advert is easy to ignore. A case study, an answer to a common objection or a reminder of what the person looked at gives them something new.
• Measure the result, not the clicks. Track enquiries and sales from these campaigns. If calls or deals close offline, our guide to offline conversion import shows how to feed them back.

Before you switch it on

• The Google tag and Meta Pixel are installed and respect the visitor's consent choice.
• The privacy policy mentions advertising cookies and the sharing of customer lists.
• Customer lists hold first-party data with the right consent, and opt-outs are removed.
• Your business is not in a sensitive or restricted category, or you have checked what the rules allow.
• Audiences are created early, since they need time to fill and Meta's do not backfill.
• Existing customers are excluded from acquisition campaigns.

Frequently asked questions

What is the difference between remarketing and retargeting?

They mean the same thing: showing ads to people who have already interacted with your business. Google Ads now calls these audiences "your data" segments, and Meta calls them custom audiences.

How many visitors do I need before remarketing works?

In Google Ads, data segments for the Display Network, Search Network and YouTube need at least 100 active visitors or users in the last 30 days before ads can serve. Meta's website custom audiences only start filling from the day you create them.

Can I upload my email list to Google or Meta?

Yes, if the data is first-party and you have the right to use it this way. Google's Customer Match policy requires a privacy policy that discloses the sharing and consent where required; Meta's terms require a lawful basis and removal of people who opted out. Neither allows data about children under 13.

Do I need consent for remarketing in the UK or EU?

Yes. Google's EU user consent policy requires legally valid consent for ad personalization from users in the EEA, the UK and Switzerland, and Google asks advertisers to pass consent signals through consent mode.

Why can't I target my Customer Match list in Google Ads?

Google's policy reserves the Targeting setting for accounts with 90 days of history and more than USD $50,000 lifetime spend. Other policy-compliant accounts can use lists for observation and exclusions.

Want your website's tags, consent banner and conversion tracking set up so remarketing works properly? See our website development service and all our services, or email [email protected].