Altruism is one of the most fundamentally social impulses, and doing things for others without expecting anything in return is core to what makes us human. This is why, from the day Facebook Platform launched in 2007, Causes has been honored to be one of the most popular applications, with over 140 million users.

When you win and you don't have anyone to share it with, why win? You have someone to share it with you.

Remember all of the 'me too' social networks built just to have a social feature Facebook and MySpace didn't have? I built one for political discussion called Essembly. It enabled unique and potentially transformative social interactions, but only 20,000 people ever used it.

For a football coach, there's nothing that matches the pain of a team not playing up to its capabilities.

As I and the rest of my Pittsburgh Steelers teammates prepared that week in late December 1974, we knew one thing: The road to the Super Bowl in the AFC went through Oakland. To achieve your dreams as a team, you had to slay the Oakland Raiders. They were the barometer of what it took to be a championship team.

Whatever you think of Facebook, you cannot fault it for lack of ambition.

When you think of me as a football player, I would like for people to think that I put it on the line every time. Good or bad, win or lose, I put it on the line.