A custom audience is a target audience created by uploading a list of emails—intended as a means for an organization to reach existing customers, newsletter subscribers, app users, etc. [1][2] Once uploaded, the emails then are matched to people on facebook; enabling advertisers to retarget their audience with 📝Ad Placements on multiple platforms.
Custom audience targeting was first launched by Facebook in September 2012 and has since been adopted by Google, Twitter, LinkedIn, and others. [3]
References
- About Custom Audiences From Customer Lists, facebook.com
- Custom Audiences from Your Website, developers.facebook.com
- Facebook Lets Businesses [...] Target Customers With Hyper-Relevant Ads, techcrunch.com