How Facebook changed our lives

What did we poor humans do before the advent of Facebook? Let's see, we smiled when we "liked" something, we dialed the phone to "update" friends and "tagging" was a kids' game.

The upside of those innocent pre-social media times: intimacy. The downside: intimacy. If you wanted to reach a huge group, it meant sending an e-mail with a cc list that looked like the phone book. At the heart of this business boom is a service that over the past decade has revolutionized and expanded -- for better or for worse -- the way humans interact. A million of us liked the site in 2004, then 250 million five years later. Today, Facebook has 1.2 billion users. Even if the site were to disappear or wildly reinvent itself in the next decade, our habits are forever altered.