Vanity Fair spends some time with Jack Dorsey, one of the original founders of Twitter, and the guy who had the idea for them to move from being a podcasting company to what they are today.

Jack is surprisingly honest about his management failures at Twitter, and I’m surprised his exit wasn’t more public for such a popular company.

Twitter usage continued growing quickly—too quickly. Dorsey and his staff struggled to keep the service from going down. Looking back, Dorsey admits he was a flawed manager: “I let myself be in a weird position because it always felt like Ev’s company. He funded it. He was the chairman. And I was this new guy who was a programmer, who had a good idea. I would not be strong in my convictions, basically, because he was the older, wiser one.” Dorsey did a poor job explaining where he wanted the company to go.

What is most interesting though, is the story of how he failed at Twitter, took what he learned and started Square, one of my favorite startups. It’s a perfect example of taking something complicated and unsexy and making it simple and sexy.

Having handed over the reins of his software firm, he had begun to make things like hand-blown colored-glass bathroom-sink handles—for $2,000 a pair. A customer, however, had to abandon a purchase because McKelvey wasn’t equipped to accept an American Express card.

In time, they conceived of a business around a free device that would be dispensed to anyone who signed up: a tiny, square-shaped credit-card reader that could be plugged into the headphone jack of an iPhone, Android phone, or electronic tablet. Unlike more complex and pricier plans set up between storeowners and credit-card companies, Square would charge the same fee to everyone (from flea-market merchants to dog-walkers to kids at lemonade stands): it’s now 2.75 percent. Says Sean Parker, the founding president of Facebook and a buddy of Dorsey’s, “Maybe Square can become for Craigslist what PayPal is for eBay.”

And his management style today:

Jack Dorsey has spent a lot of time thinking about what went wrong at Twitter. And as Square’s C.E.O., he bends over backward to be explicit, to communicate, to guide. He hosts a “town square” company meeting every Friday, where he talks about aspirations and values. To help his 78-person staff better understand why he considers design so important, he organizes trips to visit “beautiful things.” Recently—in an inadvertent echo of an episode of Mad Men (in which employees sneak into the boss’s office to gawk at his confounding new Mark Rothko painting)—Dorsey took a group to SFMoMA, where he asked them to meet at a designated time in front of a massive Rothko, its image the shape of a square.