Basics
Targeting
Targeting is choosing which people, contexts, places, devices or times should see an ad, so that the budget is spent on the audiences most likely to respond.
Targeting is the "who, where and when" of a campaign. Instead of showing an ad to everyone, advertisers narrow delivery using rules. The main families are audience targeting (who the person is or has done: Behavioral targeting, segments, retargeting, lookalikes), contextual targeting (what content they are viewing), geotargeting (where they are), and technical targeting (device, browser, operating system, connection, time of day).
Targeting data comes from many places: First-party data from the advertiser's customers, publisher data such as seller-defined audiences, third-party data from brokers, or signals in the bid request itself. Privacy laws such as GDPR and platform changes such as App Tracking Transparency limit what can be used without consent.
More targeting is not always better. Each extra filter reduces reach and raises price, and many "audience" segments are less accurate than they look. Studies of incrementality often find that broad reach with good creative beats hyper-narrow targeting.
Think of it like this
Targeting is like choosing which neighbourhoods get your flyers: sending them to streets near your shop is smarter than printing a million and scattering them from a plane.
An example
A Japanese airline targets people in Singapore and Sydney, on travel and business sites, aged 25–54, during the evening, excluding people who already booked.
Related terms
Contextual targeting
Contextual targeting places ads based on the content being viewed, such as the topic, keywords or sentiment of a page, video or app, rather than on data about the individual viewer.
Behavioral targeting
Behavioral targeting shows ads to people based on their past online behaviour, such as sites visited, searches, purchases or app use, collected over time and often across different services.
Geotargeting
Geotargeting is showing ads to people based on their geographic location, from country and city down to postcode or a small radius around a store, using IP addresses, GPS or declared location.
Retargeting
Retargeting is showing ads to people who have already interacted with a brand, for example by visiting its website, using its app or adding a product to a cart without buying.
Audience segment
An audience segment is a group of people or devices defined by shared characteristics, such as demographics, interests, purchase behaviour or intent, used to target or measure advertising.