As organizations seek to reach and engage diverse social media audiences, creating personas that accurately represent this diversity is becoming progressively important. While creating more personas generally increases the representation of demographic diversity, little is known about the dynamics between persona set size, diversity, and fairness. To study this, we collect user statistics from three organizations’ YouTube and Facebook channels and generate persona sets with varying size. Analyzing the personas’ gender, age, and country, we find that increasing the persona set size correlates with diversity in gender, age, and country. Increasing the number of personas also correlates with age fairness, while the level of diversity correlates with fairness in gender, age, and country. The results imply that organizations would benefit from using data-driven approaches to generate many personas in order to strengthen the outlooks of diversity and fairness, promoting a broader targeting strategies and inclusive design in systems and artifacts.