When Fast Company first wrote about Facebook, in 2007, the service had 19 million users. Today, it has north of 1 billion. I'd like to say that we knew Facebook would become a world-changing juggernaut. We did not. But we were convinced that social media would become an increasingly important part of business and culture, and Mark Zuckerberg offered a compelling backstory we could use to engage readers. Whether Facebook ultimately succeeded or failed, the rise of social media, we believed, was unstoppable.