Jack Dorsey quotes:

The interesting products out on the Internet today are not building new technologies. They're combining technologies. Instagram, for instance: Photos plus geolocation plus filters. Foursquare: restaurant reviews plus check-ins plus geo.

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.

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 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.

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.

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

Twitter was around communication and visualizing what was happening in the world in real-time. Square was allowing everyone to accept the form of payment people have in their pocket today, which is a credit card.

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

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.

Build what you want to see in the world.

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.

Constraints inspire us in how we approach the press, how we approach business relationships, how we do everything.

The Web provides a very easy way to immediately grasp what's going on. It really offers the transparency, so you can see, especially with the search engine, how people are using Twitter at one glance. The phone doesn't allow for that.

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.

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 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.

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

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 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.

You don't have to start from scratch to do something interesting. You don't have to start from scratch to have a massive impact on the world. You have to have a good idea. You have to convince other people of those good ideas. And you have to push as quickly as possible.

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.

The idea of Twitter started with me working in dispatch since I was 15 years old, where taxi cabs or firetrucks would broadcast where they were and what they were doing.

The first complaint we hear from everyone is: 'Why would I want to join this stupid useless thing and know what my brother's eating for lunch?' But that really misses the point because Twitter is fundamentally recipient-controlled - you choose to listen and you choose to leave. But you also choose what to put down and what to share.

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.

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.

Make every detail perfect and limit the number of details to perfect.

What's interesting about Twitter and the influencers that someone follows - like, say, Shaquille O'Neal - is that they see someone who is using the exact same tools that they have access to, and I think that inspires this hope to be able to really engage with someone like him.

Everything we do is about getting people to be more open, more creative, more courageous.

TweetDeck is a very interesting client, because it presents a view that no other client in the world presents, which is this multicolumn, massive amounts of information in one pane. And people really, really enjoy that.

It's empowering to be asked to look at what's possible, not told how to do it.

The greatest lesson that I learned in all of this is that you have to start. Start now, start here, and start small. Keep it Simple.

Making something simple is very difficult.

Success is never accidental.

We get to design what we want to see in the world rather than doing what other people think should be done.

Your job as an executive is to edit, not write. It's OK to write once in a while but if you do it often there's a fundamental problem with the team. Every time you do something ask if you're writing or editing and get in the mode of editing.

An idea that can change the course of the company can come from anywhere.

Revolution looks at the intersection ahead and pushes people to do the right thing.

You don't have to start from scratch to have a massive impact on the world.

Great companies don't just have one founding moment. They have many founding moments.

The strongest thing you can cultivate as an entrepreneur is to not rely on luck but cultivating an ability to recognize fortunate situations when they are occurring.

All my days are themed. Monday is managementTuesday is product, engineering, and design. Wednesday is marketing, growth, and communications. Thursday is partnership and developers. Friday is company and cultureOn the days beginning with T, I start at Twitter in the morning, then go to Square in the afternoon. Sundays are for strategySaturday is a day off.

Life happens at intersections.

I spend 90% of my time with people who don't report to me, which also allows for serendipity, since I'm walking around the office all the time. You don't have to schedule serendipity. It just happens.

Technology to me does two things: it increases the velocity of communication and increases the number of people who can participate. That's it. That's really all technology for our entire history has ever done.

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

Short term satisfaction will never lead to something timeless.

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

Don't avoid eye contact and don't be late

Those words are from Lynda Barry's novel 'Cruddy.' I've carried them with me for some time. There's a lot in my life I wasn't expecting. One is the realization that I stood at this pulpit and delivered a reading for my own graduation...15 years ago. Unexpectedly, I'm old.

I think that great programming is not all that dissimilar to great art. Once you start thinking in concepts of programming it makes you a better person...as does learning a foreign language, as does learning math, as does learning how to read.

Twitter is the world.

My mom cares that I tweeted a picture of my breakfast. She's knows I'm eating and I'm safe.

From a product standpoint, we want every touch point to feel magical. It inspires trust.

'Luck' is recognizing when the situation encourages build out and execution.

As CEO, my main job is editor-in-chief.

Meet customers where they are; question how to make the tools customers use more valuable,

My goal is to simplify complexity.

Amazing what people make up based on what they choose to see.

It's really complex to make something simple.

Pick a movement, pick a revolution and join it.

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.

Starting anything is a roller coaster with the highest highs and lowest lows.

Everyone has an idea, but it's really about executing the idea and attracting other people to help you with the idea.