Definition:

Retargeting is a digital advertising strategy that directs ads to people who have previously interacted with a website, application, advertisement or another brand asset. Audiences can be defined from actions such as visiting a page, viewing a product, starting a purchase or playing a video.

Its purpose is to reach an audience again after they have shown some sign of interest. This does not guarantee a conversion: results depend on the offer, targeting, creative, post-click experience and available measurement.

How retargeting works

Advertising platforms commonly create audiences in two main ways:

Tags, pixels and identifiers: A tag installed on the website or application records permitted events and associates them with browser, device or account identifiers. Cookies may be involved in this process, but they are not the only mechanism available.
First-party lists: A company can upload customer or contact data for the platform to attempt to match it with its users. The data must have been obtained and used on a valid basis and in accordance with the platform’s terms.

The availability of each method depends on the channel, browser, device, consent and privacy restrictions. Matching a person with an audience does not mean that the advertising account can identify that person individually.

Retargeting evaluation

Its main advantages and limits depend on how audiences, advertising pressure and measurement are configured:

Behavioural targeting: It can distinguish audiences according to the pages, products or actions with which they have interacted.
Adapted messages: Ads can respond to a particular stage of the journey, provided that the personalisation is relevant and not intrusive.
Investment control: Campaigns can use their own budgets, bids, membership windows and frequency limits.
Measurement subject to restrictions: Attributed conversions depend on the configuration, attribution models and available information. People who have already completed the action should be excluded when further advertising is not appropriate.

Excessive exposure can cause annoyance or waste budget. Planning should therefore cover frequency, audience duration, exclusions and creative review, as well as consent and data-protection requirements.

Scope of retargeting

Retargeting is commonly used to describe re-engagement through ads in search, display or social networks. Remarketing can be used in a broader sense that also includes email or other relationship channels.

In professional usage: The two terms are frequently used as synonyms for advertising campaigns aimed at previous audiences.
On platforms: The name depends on the provider. For example, Google Ads uses the term remarketing for several forms of list-based advertising.

In practice, the meaning depends on the context and provider. When planning a campaign, it is more useful to define the audience, channel, data and objective than to infer how it works from the name alone.