When people come to Twitter and they want to express something in the world, the technology fades away. It's them writing a simple message and them knowing that people are going to see it.

You can follow your favorite company or organization. You can also mix that in with your family and your social network and talk about all these interests in real time. That's the value, not the brand 'Twitter.' Twitter just provides the venue for it.

I fell in love with flora of all types, especially ferns. Loved the sparse structure and repetition of shape - almost fractal.

I think Twitter is the future of communications and Square will be the payment network.

I was fascinated with jeans, because you can impress your life upon the jeans you wear. The way you sit imprints on the jeans.

My goal is to simplify complexity. I just want to build stuff that really simplifies our base human interaction.

There's an entire universe in every single tweet, and it all really depends on the content as far as how it's going to spread.

Twitter has been my life's work in many senses. It started with a fascination with cities and how they work, and what's going on in them right now.

What I love about New York is just the electricity I feel right away.

A number of people in the United States, almost everyone, is using plastic cards to pay for things, but it's extremely difficult to accept these cards. So let's make it's easy and take more and more of the friction out as we can.

Anything you're interested in the world - whether it be Charlie Rose or JetBlue or a public figure or your local coffee shop - they're on Twitter and broadcasting what is interesting to them.

I am someone who tweets about what I have for breakfast, what I have for lunch, what I have for dinner, and for 99.99999 percent of the world, it's useless. It's meaningless. But for my mother, she loves it.

I love cities, and I love city governments in particular. But in politics it would have taken me 8 years from implementing a policy before I would get to see the feedback. With programming I could model the same policies and see the impact immediately. Technology is a far more efficient way to test.

I loved couriers. You had this transfer of physical information happening throughout the city and the world. Someone picking up the package, putting it in a bag, going somewhere, taking it out of the bag, giving it to someone else. I thought that was so cool. I wanted to map it, to see that flow on a big screen.

I said a long time ago that Foursquare can make cities better. You have these augmented realities like Foursquare and Twitter and Facebook that provide these virtual nodes and instant feedback from anywhere, adding annotation around a physical places.

I think Twitter is best when it sparks conversations elsewhere. To use YouTube and Facebook and all the tools we have available to us today to respond and also promote and answer and engage is awesome.

I'm less interested in how people are following each other and more interested in how they are following topics and tweets themselves. People are following more key words and concepts and more ideas and acting on those rather than individuals or organizations.

IM is interesting because you look at your buddy list and, at a glance, see what your friends are listening to, what they're working on, what they're doing. The problem was that you were bound to the computer keyboard.

It's a matter of invitations versus context. Twitter is really good at providing context, like, I''m having coffee at Third Rail Coffee.' Foursquare is about invitations to places. In this respect Foursquare has started to replace Yelp for me.

People who are using it to sell things on Craigslist to holding garage sales - campaigns - the Obama campaign and the Romney campaign both used Square to raise funds.