An Engagement Custom Audience is a Custom Audience made up of people who have engaged with your content across the Facebook family of apps and services.

"Engagement" refers to actions such as spending time viewing your videos or opening your lead form or Canvas. Using Engagement Custom Audiences, you can target ads to people who've taken these actions. You can also use it as a source for a Lookalike Audience, which will let you find people who are similar to those who've engaged with your Facebook content.

Here are the engagement types available, broken down by Engagement Custom Audience type:

• Video
• Lead form
• Canvas/collection
• Facebook Page
• Instagram business profile
• Event

Bear in mind that

• Engagement Custom Audiences are different to Custom Audiences from your website. While both do take actions into account, Engagement Custom Audiences use actions taken on Facebook's family of apps and services, whereas Custom Audiences from your website use actions taken on your website tracked by a pixel (otherwise known as "events").
• When you create an Engagement Custom Audience, you tell us how many days you want us to go back when collecting engagement. This means that if you tell us to look back 30 days and someone engaged 29 days ago, that person will be in your audience. However, if they fail to engage the next day, they will then be removed from it. Anyone new who engages within the time period you choose will be added to the audience. This means that the audience is constantly being refreshed, so you don't need to edit or create a new Engagement Custom Audience unless you want to change the time period or the type of engagement.

* Nguồn: Facebook