San Francisco (AFP) – Twitter’s newest board member and largest stakeholder Elon Musk tweeted Saturday to ask if the social media network was “dying” and to call out users such as singer Justin Bieber, who are highly followed but rarely post. “Most of these ‘top’ accounts tweet rarely and post very little content,” the Tesla boss wrote, captioning a list of the 10 profiles with the most followers — a list which includes himself at number eight, with 81 million followers. “Is Twitter dying?” he wrote. Former US President Barack Obama appears at the top with 131 million followers, followed by …