Twitter has hired the former Pearson chief executive Dame Marjorie Scardino to be the first woman on its board, after critics rounded on its all-male lineup. In response to the company's announcement, the former boss of the Financial Times publisher acknowledged the news in what appeared to be her first tweet: “@twitter Thank you. There couldn't be a more exciting time in Twitter's history to join!” she wrote. Twitter said Scardino would join the company immediately and would be a member of its audit committee.