Twitter has officially named Jack Dorsey its new permanent CEO

Twitter Inc. named Jack Dorsey as chief executive officer, betting its co-founder and former leader can revive fortunes at a social-media company that has failed to impress investors since its 2013 initial public offering. Dorsey, 38, will also keep his job as CEO of mobile-payments company Square Inc., the payments and financial services company he co-founded in 2009, Twitter said in a filing Monday. “My focus is to build teams that move fast, and learn faster,” Dorsey said in a tweet. “In the past 3 months we have increased our speed and urgency at both companies.” Twitter’s board is turning back to one of the people who started the San Francisco-based company to reignite the product buzz that lured millions of users early on. Dorsey helped pioneer the idea that anyone could use short blogs of no more than 140 characters to share views widely and build followings. Twitter became the go-to platform for reporters, entertainers, politicians, activists and others. Yet in recent years the site has been plagued by management turmoil and a product slowdown while rival sites gained in popularity.