The action of marking an electronic message within an email system to denote its significance or require a specific action. For instance, a user might mark an email containing a task assignment to serve as a reminder to complete that task. This visual cue helps prioritize and organize email correspondence.
This feature enhances email management by enabling users to quickly identify important messages requiring attention. It allows for efficient task management, improved responsiveness to time-sensitive items, and better overall organization of an inbox. Historically, this functionality evolved from physical methods of marking paper documents for follow-up.