The concept of user deduplication is crucial for managing a corpus of user-related data and can be achieved using various methods, including batch processing or real-time solutions. A traditional approach involves running all user information through an application to match records based on defined heuristics, but this method often results in stale data due to the need for batch or scheduled actions. In contrast, Couchbase Eventing provides a new option for effective deduplication using real-time functions. By setting up four buckets (metadata, staging, fieldindex, and users) and creating a function called "dedupe", developers can develop a real-time user deduplication engine in just 50 lines of code. The function uses helper functions to parse documents, find matches, and update the index, ensuring that duplicate users are removed and canonical users are created. This approach allows for flexibility and customization, making it possible to adapt to various use cases and fields beyond just user emails.