Actions are executed after a reaction is created. These can run right after a reaction was created, updated or deleted, or anytime later. Actions can even be executed at regular time intervals.
Actions include sending notifications, updating a business intelligence API or sending monthly reports.
Example of a notification: Say user A writes a movie review. User B comments on the review. User A now receives a notification on the action.
Example of a report: Say you run an online shop where users can write product reviews. Actions allow you to generate monthly reports with a spreadsheet displaying all the reviews on a certain product category to the category manager.