Dick Costolo

(Newser) - Dick Costolo is stepping down as CEO of Twitter after about five years. The company announced the news in a press release but provided no explanation. CNBC doesn't sound shocked, however: "Many investors and analysts have called for a shakeup amid a sluggish run for Twitter's stock,...

(Newser) - Twitter co-founder and CEO Evan Williams is relinquishing leadership of the microblogging site to COO Dick Costolo, reports the Wall Street Journal . "Building things is my passion," Williams offers as explanation for the move, adding that he asked Colstolo to take over. Adds Costolo, recently "it became...