Jack Dorsey is officially back as Twitter chief executive. What does that mean for Twitter?
Jack Dorsey is now the permanent chief executive at Twitter. Above, Dorsey and co-founders Evan Williams and Biz Stone, wait for the opening bell to be rung at the New York Stock Exchange, Thursday, Nov. 7, 2013.(AP Photo/Richard Drew) For nearly four months, Twitter has been searching for a chief executive to help it reach a larger, broader audience....