Lara Logan: Were you angry?
Jack Dorsey: Yeah. I was angry. I was angry at-- you know, the board. I was angry at my co-founders. I was angry at myself.
Lara Logan: You once described it as being like a punch in the guts.
Jack Dorsey: Yeah.
Logan: No grudges? You don't hold any grudges?
Jack Dorsey: I'm stubborn but I don't necessarily hold grudges.
Two and a half years later, new management at Twitter invited him back to help run the company. And Dorsey accepted. Suddenly he had two jobs. By then he had dreamed up a new company, Square, that he believes can also change the world. And he says he runs it differently than Twitter. Decisions made behind closed doors are sent out immediately on the company's mass email system including sensitive information on company goals and profits. Dorsey roams around the office, available to talk to anyone.
Lara Logan: Do you have an office here?
Jack Dorsey: I don't. I don't have an office. I don't have a desk.
Lara Logan: You don't have a desk at all, even, like--
Jack Dorsey: I don't have a desk. I have my iPad.
While Twitter is about messages, Square is about money. It permits anyone with a smart phone to become a merchant. The concept grew out of a brainstorming session with a friend named Jim McKelvey, who was both a software ace and a frustrated artist.
Jack Dorsey: He was at an art fair and he couldn't sell a piece of glass because he couldn't accept a credit card. So, that was, you know, $2,000 lost. And he just got fed up with that. And he came out to San Francisco that next week and we spent the week trying to figure out why no one has done this before.
Lara Logan: And this, at that moment, was what?
Jack Dorsey: Well, we didn't know what it was. It was a way to accept credit cards on your phone. That's all we knew.
The software is simple and it's fast -- two qualities that are most important to Dorsey. To take a payment, you swipe a customer's credit card through a white square that plugs into the earphone jack.
Jack Dorsey: So you just take the card, you swipe it through...
The customer signs a receipt electronically. Department stores don't use it yet, but millions of small business people do.
Jack Dorsey: 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.
Dorsey says merchants like Square because the fee is less than some credit cards charge. And business at Square is booming...accelerating in four years from zero to $15 billion in annual transactions.
Jack Dorsey started thinking about the software he's built in Silicon Valley nearly 30 years ago when he was growing up in St. Louis. He had a speech impediment as a kid and spent a lot of time alone at home, playing with computers when he was eight. He taught himself how to build computer programs before he was a teenager. Dorsey was fascinated by trains and maps and he used to spend hours down at these train yards.
Lara Logan: Most kids would have pictures of football players and girls on their walls or their favorite bands.
Jack Dorsey: Right.
Lara Logan: And you've got maps.