I spent most of my career, including my time at McKinsey, never acknowledging that I was a woman. And, you know, fast forward - I'm 43 now - fitting in is not helping us.

Facebook is great for women and men. We are enormously flexible. We care a lot about great opportunities for women, we push ourselves to make things as flexible as possible.

Men can comfortably claim credit for what they do as long as they don't veer into arrogance. For women, taking credit comes at a real social and professional cost.

I've seen over and over how much self-belief drives outcomes. And that's why I force myself to sit at the table, even when I am not sure I belong there - and yes, this still happens to me. And when I'm not sure anyone wants my opinion, I take a deep breath and speak up anyway.

I have never worked for a woman, and I have never worked with a lot of women.

When you're more valuable, the people around you will do more to make it work.

Until women are as ambitious as men, they're not gong to achieve as much as men.