Facebook started as a service for Harvard students but expanded because almost everyone has friends and family they want to stay connected with.

I initially built Facebook for myself as a college student, but I quickly realized its potential to serve a broader audience beyond just my university.

At the time of Yahoo's offer, Facebook had 10 million users, and it wasn't clear that we would succeed beyond that point, leading to intense discussions within the company about whether to sell or continue building.

Facebook's growth was initially slow, taking a year to reach a million users, but this time allowed us to refine the product and ensure it met user needs effectively.

I created Facebook because my friends and I wanted a way to connect with others at Harvard, not because I thought it would become a company.

When I first met Mark Zuckerberg, I was struck by his vision and confidence, predicting Facebook would have 300 million users, which it far exceeded.

Facebook's growth forecast was initially underestimated; they grew to over 2 billion users by being intentional about growth strategies.

The size of new markets is often underestimated; LinkedIn and Twitter were initially dismissed as features but became significant companies.

Facebook's success was due to secure connections and ensuring that new users had at least 20 friends on the platform, which made it more engaging.