The twitter accounts of US president-elect Barack Obama, singer Britney Spears and other prominent figures were hacked last month and fake messages were sent out in their names on the micro-blogging service. Twitter founder Biz Stone, in a post on the official company blog, said a total of 33 Twitter accounts had been hacked including those of Obama and Rick Sanchez, a CNN television anchor with tens of thousands of followers. “We immediately locked down the accounts and investigated the issue”, Stone said. Because of “transition issues”, Obama has not updated his twitter since winning the US presidential election in November. Twitter, which allows user to post real-time updates of 140 characters or less, has an estimated four to five million users according to a recent study.