How does the platform know who visited?
Through the tracking it already runs on your site. The Meta Pixel and the Conversions API tell Meta which browsers and accounts viewed a page, added to a cart or bought. The Google tag does the same for Google Ads. Each visit puts the person in a list, with a window: Meta keeps a website visitor in a custom audience for up to 180 days (Meta Business Help Centre, "About website custom audiences") and Google Ads keeps a remarketing list member for up to 540 days. You choose the window and the behaviour: everyone who visited, people who viewed a product, people who started checkout and left.
A retargeting campaign then targets that list, and only that list. Nobody who has never heard of you sees it.
Why is it cheap, and why does that mislead?
It is cheap because the hard part is done. The person already found you, looked, and perhaps nearly bought. A nudge converts a far higher share of them than a cold audience, so the cost per sale is low and the ROAS is high. Owners see a ROAS of 8 on retargeting next to a ROAS of 1.8 on the campaign that finds new people, and move the budget to the one that "works".
That is the trap. Retargeting cannot exist without the cold campaign feeding it visitors, and a share of the sales it claims would have happened anyway: the person was coming back, and the ad happened to be the last thing they saw. The platform's attribution gives the ad the credit. Cut the cold campaign and the retargeting audience empties within the window, and the ROAS of 8 goes with it.
Blended ROAS = (cold revenue + retargeting revenue) ÷ (cold spend + retargeting spend)
($5,400 + $3,200) ÷ ($3,000 + $400) = 2.5
What does a month of both look like? (example figures)
A Perth furniture maker spends $3,400 a month on Meta ads, split between a cold campaign to new people and a retargeting campaign to the last 30 days of visitors who did not buy.
| Cold campaign | Retargeting | Together | |
|---|---|---|---|
| Spend | $3,000 | $400 | $3,400 |
| Revenue Meta credits | $5,400 | $3,200 | $8,600 |
| ROAS | 1.8 | 8.0 | 2.5 |
| People reached | 41,000 | 2,600 |
The honest number is 2.5, and whether that makes money depends on the maker's gross margin: at 45 percent, break-even is a ROAS of about 2.2, so the pair is just ahead. Moving the $3,000 into retargeting would not produce a ROAS of 8 on $3,400. It would show the same 2,600 people the same ad fifteen times, which is where frequency becomes fatigue.
When is retargeting worth running on its own?
When the visitors arrive without ads. A business with steady traffic from Google search, a Google Business Profile or word of mouth has a warm audience it is not paying for, and a small retargeting budget turns some of those visits into sales at a cost nothing else matches. A tradie whose website gets 400 visits a month from local searches can run a $5 a day retargeting campaign to the ones who did not call, and the sums work because the cold half of the job was free.
What does Cora do with retargeting?
CoraVision reads your Meta and Google Ads campaigns every night once they are connected, campaign by campaign, with their spend, results and the value of those results, so a retargeting campaign and the cold campaign that feeds it sit side by side in the same numbers. Mira, the Meta Ads specialist, reads the two together rather than letting the high one carry the account, and when a strategy in your plan calls for retargeting, the steps to build the audience and exclude past buyers are taught on your own screen in pill mode. CoraVision never creates or changes a campaign itself.
Questions
How long does someone stay in a retargeting audience?
As long as the window you set. Meta keeps website visitors in a custom audience for up to 180 days after their visit, and Google Ads remarketing lists can keep someone for up to 540 days. Shorter windows, seven to thirty days, reach people while they still remember you and cost less in wasted views.
Is a retargeting ROAS of 8 real?
The sale is real. The credit is generous. Many of those buyers were coming back anyway, and the ad was the last thing they saw before they did. Read a retargeting campaign next to the campaign that brought those people in the first time, and judge the pair together.
Why do I see ads for things I already bought?
The advertiser did not exclude buyers from the audience. Every platform lets you remove people who completed a purchase, and a retargeting campaign that keeps chasing them is wasting the cheapest money in the account.