A Custom Audience is a targeted advertising segment created by an advertiser using their own data sources. This allows advertisers to reach specific groups of users who have already interacted with their business or are part of a defined customer list. Custom Audiences are widely used in digital advertising platforms such as Facebook Ads, Google Ads, and others.
Data sources for Custom Audiences can include website visitors, app users, email subscribers, or customer lists (such as email addresses or phone numbers).
Utilizing Custom Audiences enables advertisers to re-engage existing customers, upsell, cross-sell, or exclude current customers from certain campaigns.
Data is typically hashed and anonymized to protect user privacy.
Here is an example:
​
A retailer uploads a list of past purchasers’ email addresses to a platform like Facebook Ads to show them a new product promotion.