Jack Dorsey: Twitter star seeking investors The co-founder has kept the social network true to its simple principles, writes Tim Bradshaw Just setting up my twttr. When Jack Dorsey tapped out that maiden 34-character tweet back in March 2006, Twitter was the side-project of a failing San Francisco start-up. Seven years and hundreds of billions of tweets later, TWTR will be the stock market ticker of a public company worth more than $12bn, chaired by Mr Dorsey in the hottest initial public offering since Facebook. Mr Dorsey's own journey between then and now mirrors that of the messaging site itself. Just as Twitter was the ugly duckling that became a swan, so Mr Dorsey has exchanged his punk 2006 look - complete with nose ring and mathematical forearm tattoo - for expensive suits and supermodel friends like Lily Cole commensurate with his status as one of Silicon Valley's slickest stars. The 36-year-old is now handsome and rich enough that his romantic life is raked over by tabloids. Person in the news Twitter's IPO, details of which were announced this week, is a vindication of Mr Dorsey's vision of the free, open and chaotic communications tool that takes the pulse of the planet. Its 140-character cacophony puts the mundane on equal footing with the profound - letting anyone send messages to Rihanna, the Iranian president or their mum. It mingles live news with arguments about reality TV shows. For its earlier investors, the IPO also proves that advertising can be a lucrative part of that mix, making hundreds of millions of dollars in annual revenues by charging marketers to "promote" their tweets. Although credit for growing sales lies more with Twitter's current chief executive, Dick Costolo, Mr Dorsey's advocates argue that he played a crucial role in ensuring the ads served the product, rather than overwhelming it. This, some say, marks him out over rivals such as Mark Zuckerberg, chief executive of Facebook, where advertising has not always been such a "native" part of the user experience. Also unlike Mr Zuckerberg or Google's founders, who still exert considerable control over their company through dual-class voting shares, a series of management changes and fundraisings since Mr Dorsey co-founded Twitter mean that he is less involved with the company he helped shape. Indeed, after founding two multibillion-dollar companies, Mr Dorsey is chief executive of only one: Square, a mobile commerce platform. Yet it is still Twitter that embodies the son of a pizza restaurant owner from St Louis. He's very cerebral. When he does speak he wants to make sure that it's thought-through and concise," says Mike McCue, chief executive of Flipboard, a digital magazine app, and a former Twitter board member. He's kind of like Twitter personified: he speaks in 140-character bursts. Mr Dorsey says he never wanted to be an entrepreneur: he wanted to be an artist, sailor, tailor - or Bruce Lee (he went through a period of tweeting quotes from the martial arts master). He studied computer science and mathematics at New York University - but did not complete the course. A fascination with how cities work led Mr Dorsey into software development for a courier dispatch company. He won the job by hacking into its IT systems to demonstrate his skills. Six years later, while working at Odeo, a San Francisco podcasting company that was being steamrollered by Apple's iTunes, Mr Dorsey and colleague Noah Glass sketched out an idea for a status-updating service that turned into Twitter. Mr Dorsey became its chief executive when, after gaining a geek following in early 2007, Twitter spun out on its own. Evan Williams - another San Francisco entrepreneur who owned Odeo - was then Twitter's main financial backer. However, the two clashed; in late 2008, Mr Dorsey was forced out of the chief executive role, becoming chairman. In a 2011 Vanity Fair interview Mr Dorsey described the experience of being ousted as "like being punched in the stomach" but admitted his deficiencies as a manager. However, he picked himself up, turning to what a former colleague says is a 10-point list of ideas to change the world. In early 2009 he co-founded Square with fellow St Louis native Jim McKelvey, who had given an awkward 15-year-old Mr Dorsey his first tech job, archiving documents on to CD-ROMs. Two years later, Square's credit-card reader, which plugs into an iPhone or iPad, was processing $2bn a year. That figure now exceeds $15bn and Square's valuation has been reported at more than $3bn. "I was always most impressed with Jack's long-term vision when it came to building Square's business," says Megan Quinn, a former director of products at the company and now partner at KPCB, an investor in both Twitter and Square. He's not afraid to take risks, and he's not afraid to start over. Starting over is exactly what Mr Dorsey did at Twitter when he returned in 2012 to lead product development. Mr Williams had been replaced by Mr Costolo in 2010, in an acrimonious departure over the pace of revenue growth. For several months, Mr Dorsey worked eight hours at each of his companies every day: "#200%," he tweeted. Taking a role he likened to editing a newspaper, he pushed for a simpler product. Some employees say he expended more effort on the "big picture" than practical details. While Mr Williams, Mr Costolo and many others all deserve credit for Twitter's success as a business, Mr Dorsey provided product continuity, which has survived seven years of frenetic growth and management turmoil. "It's really complex to make something simple," he told Charlie Rose, a TV interviewer, in 2011. Last month Mr Dorsey took a helicopter ride around the Golden Gate Bridge, a structure he says is the "perfect intersection between art and engineering." One day before Twitter announced the IPO was coming, Mr Dorsey tweeted a "selfie" of himself at the helicopter's controls, captioned: "Now I get to fly." The writer is the FT's San Francisco correspondent