Twitter is winning war on trolls and extremists, says its Europe chief

These are critical times for Twitter. The social media giant, which is 10 years old in March, has amassed 320 million users and a valuation of more than $33bn (£22bn). But it desperately needs to turn back waves of negative headlines and to find ways to engage more deeply with the margins of its audience. Twitter’s recent history has been beset by stories of trolling and extremism. Celebrity users, the great cheerleading asset for the platform in its fledgling years, have been closing their accounts. Many of them have been women.