December 2010. Jack Dorsey invented Twitter because he was a weird kid who couldn't stop staring at maps. He grew up in St. Louis. By age eight, his bedroom walls were covered with maps torn from magazines and gas stations. He walked the city constantly, watching trains, taxis, and police cars move through it. When his dad brought home an IBM PC Jr., Dorsey taught himself to code for one reason: he wanted to draw his own maps on the computer. At 14, he started listening to emergency dispatch radio. Police scanners, ambulance frequencies. He wrote software that could plot those vehicles as moving dots on his digital maps. Each dot had a meaning: here's who you are, here's where you are, here's what you're doing. He was tracking real-time city movement from his bedroom in Missouri. By 15, he'd written dispatch routing software that some taxi companies kept using for decades. In this interview, he explains exactly how that obsession became Twitter. The concept is pure dispatch: "Someone broadcasts a message and whoever is interested follows." That's how ambulance dispatchers work. A message goes out, and whoever needs it, listens. Everyone else ignores it. He actually built a prototype in 2000. A Blackberry 850, a ten-person email list. He walked to the bison paddock in Golden Gate Park and sent a message: "I'm at the bison paddock." It went to all ten people. He noticed that other BlackBerry users were weirdly interested in the fact that he was standing near some bison. That was the first tweet. Six years before Twitter existed. He shelved it. Went back to dispatch work. The timing wasn't right. In 2005, he joined Odeo, a podcasting startup. The month after he arrived, Apple launched its podcast directory in iTunes, effectively killing its business. Morale collapsed. The CEO asked everyone for new ideas. Dorsey pitched the dispatch thing again: let people broadcast short status updates over SMS. Built a prototype in two weeks. Noah Glass found the word "twitter" in the dictionary: "a short burst of inconsequential information, and chirps from birds." They needed a five-character SMS shortcode, so they stripped the vowels. TWTTR. That code was already taken, so they added a subscriber line, and it became the Twitter we know. They also invented the words "follow" and "unfollow." Those didn't exist before. Dorsey's concept was a blank wall. You write on it. People walk up and read it when they want. They leave when they don't. Follow and unfollow. Then he tells the Square origin story. His co-founder, Jim McKelvey, a glass artist he'd known since he was 15, called him one day and said he'd just lost a $2,000 stained-glass sale because he couldn't accept a credit card. They both had iPhones. Computers in the palm of their hand, but no way to take a payment. They decided to fix that. Within a month, they had a prototype: a small reader plugged into an iPhone headphone jack that could swipe a card. Dorsey first tweeted on March 21, 2006. Twitter went public in November 2013 and was eventually sold to Elon Musk for $44 billion in 2022. Block, the company formerly known as Square, is worth about $40 billion today. All of it traces back to a kid in St. Louis tracking ambulances on a map he drew himself. Video: Jack Dorsey @jack interviewed by Kevin Rose @kevinrose on "foundation," circa 2011. This was during Square's early days. original footage from Foundation/Kevin Rose.