Twitter has apologised for allowing adverts to be micro-targeted at certain users such as neo-Nazis, homophobes and other hate groups. The BBC discovered the issue and that prompted the tech firm to act. Our investigation found it possible to target users who had shown an interest in keywords including “transphobic”, “white supremacists” and “anti-gay”. Twitter allows ads to be directed at users who have posted about or searched for specific topics. Hope Not Hate, an anti-extremism charity, said it feared that Twitter’s ads could become a propaganda tool for the far-right. “I can see this being used to promote engagement and deepen the conviction of individuals who have indicated some or partial agreement with intolerant causes or ideas,” said Patrik Hermansson, its social media researcher.