The Facebook People Taking Action metric measures the number of unique people who take any action after viewing your ad.
When you compare this number with your total reach you can quickly identify what percentage of the people who see your ad have engaged with it.
It is important to remember that one person can take multiple actions related to your advertisement. For example, a user might click to expand the photo you use in your ad creative. After doing that, they may return to your ad and click on your link. The Facebook Pixel could then detect that the user has reached your website or performed a key activity.
Facebook uses this metric to report the number of unique people taking action, not the total number of actions.
The metric may vary as it is based on sampled data.
A number of different actions in the Facebook People Taking Action metric, some of which aren’t always easily found in the ads report. These often include:
Desktop App Actions
Desktop App Installs
Desktop App Engagement
Desktop App Story Engagement
Desktop App Uses
Mobile App Actions
Mobile App Installs
Mobile App Sessions
Mobile App Registrations Completed
Mobile App Content Views
Mobile App Searches
Mobile App Ratings Submitted
Mobile App Tutorials Completed
Mobile App Adds To Cart
Mobile App Adds to Wishlist
Mobile App Checkouts Initiated
Mobile App Adds of Payment Info
Mobile App Purchases
Mobile App Levels Completed
Mobile App Achievements Unlocked
Mobile App Credits Spent
Page Engagement Actions
Page Tab Views
Post Engagement Actions
Website Checkouts (via Facebook Pixel)
Website Registrations (via Facebook Pixel)
Website Leads (via Facebook Pixel)
Website Key Page Views (via Facebook Pixel)
Website Adds to Cart (via Facebook Pixel)