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.

If more women are in leadership roles, we'll stop assuming they shouldn't be.

A lot of people will say, "what's Facebook's business model?" I always find that a kind of funny question. Our business model is out there, which is: we monetize largely through advertising and a little bit through the gift revenue, the virtual gifts we have on our site. I think those continue to be the most promising avenues going forward.

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.

At Facebook we feel a lot of affinity not just for this community but for any community that is trying to do what Davos is trying to do, which is to share information. And Davos is doing it in a particular way - I think the Facebook approach is obviously more broad-based, we're trying to include everyone in the world. But the goal is the same: bring people together, to share information and make the world more connected, and have people have a deeper understanding of themselves, others, the communities of which they want to be a part and can be a part.

I believe we need affordable child care. I believe we need flexibility. I believe we need institutional reform and public policy reform.

We have to ask ourselves if we have become so focused on supporting personal choices that we're failing to encourage women to aspire to leadership.