We should have a society that measures progress not just by economic metrics like GDP, but by how many of us have a role we find the meaningful. We should explore ideas like universal basic income to make sure everyone has a cushion to try new ideas.

The thing that we are trying to do at Facebook is just help people connect and communicate more efficiently.

Facebook is inherently viral.

I actually do think you're seeing this trend towards organizations just caring more about their brand and engaging. And so I think Home Depot will want to humanize itself. I think that's a lot of why companies are starting blogs, are just giving more insight into what's going on with them.

People influence people. Nothing influences people more than a recommendation from a trusted friend. A trusted referral influences people more than the best broadcast message. A trusted referral is the Holy Grail of advertising.

Facebook is inherently viral. There are lots of sites that include a contact importer, and for lots of them it doesn't really make sense. For Facebook it fits so well. It wasn't until a few years in that we started building some tools that made it easier to import friends to the site. That was a huge thing that spiked growth.

The days of you having a different image for your work friends or co-workers and for the other people you know are probably coming to an end pretty quickly. Having two identities for yourself is an example of a lack of integrity.