Is there an existential threat of social media?

The answer to the blank space is voice. There are four types of employees besides stars, and they are: land mines, not yet gone, and students.  

These employees are classified into the four categories based on two important questions: Is this employee a cultural fit? Is the employee a contributor?  

Stars would fit culturally and be an active contributor, while students are culturally fit but not yet a contributor. Land mines are not culturally fit but are active contributor while not yet gone are both not culturally fit and not active contributor.