What is retargeting?
Retargeting is the practice of showing ads to people who have already engaged with your brand, such as visiting your website, opening your app, viewing a product or adding something to a cart. The goal is to bring them back to finish an action they started. Because these people already know you, retargeting audiences usually respond better than cold audiences.
Google and some other platforms call the same tactic remarketing.
How retargeting works
Tag: a tracking pixel on your site or an SDK in your app records visits and actions.
Collect: each visitor's identifier, such as a cookie, mobile advertising ID or logged-in ID, is added to an audience list based on what they did.
Set a window: each list has a membership duration, for example 30 days for site visitors or 7 days for cart abandoners.
Bid: when a listed user appears in a bid request, the DSP recognizes the identifier and bids to show your ad.
Stop: a conversion tag removes people who bought, so you stop paying to reach them.
Common retargeting segments
All site visitors, for broad reminder messaging.
Product or category viewers, often paired with dynamic creative showing the items they looked at.
Cart or form abandoners, the highest-intent group.
Past customers, for repeat purchase or cross-sell.
Identity has changed how retargeting works. Chrome still supports third-party cookies, but Safari and Firefox block them and consent rules limit their use, so cookie-based lists reach fewer people than they used to. Retargeting now leans more on first-party data, logged-in environments and IDs such as UID2.
Why retargeting matters
Most visitors leave without converting. Retargeting gives you a second chance with people who already showed interest, usually at a lower cost per result than prospecting.
It also supports the rest of your media. Visitors who first arrive from search, social or video ads can be reminded of your offer, so the money spent to bring them in is not wasted after one visit.
Two cautions keep it healthy. First, use frequency capping so people are not followed by the same ad all day. Second, test whether it actually adds sales. Retargeting reaches people who were often going to buy anyway, so platform reports can overstate its value. An incrementality test with a holdout group gives the real answer.
Retargeting vs remarketing
In practice the terms mean the same thing, and Google uses remarketing as its product name. Some marketers use remarketing in a narrower sense for re-engaging past customers by email. In programmatic display and video, both words describe showing ads to people who already know your brand. Whatever you call it, the mechanics are the same.
Retargeting with AdGeeks
In DV360 and Adform, retargeting runs on your own site and app audiences. Amazon DSP adds audiences based on Amazon shopping activity, such as people who viewed your products. AdGeeks traders set windows, caps and exclusions, and keep retargeting in proportion to prospecting.
