The Twitter logo is seen on a sign at the company's headquarters in San Francisco, California on November 4, 2016. (Photo credit should read JOSH EDELSON/AFP via Getty Images) Former Ku Klux Klan leader David Duke has been banned from Twitter for breaking the social media platform's site’s rules forbidding hate speech.The company said Friday that Duke's account “has been permanently suspended for repeated violations of the Twitter Rules on hateful conduct.”It didn't specify what exactly Duke posted that triggered the ban, but its policy on hateful conduct prohibits promoting violence or threatening attacks against people based on religious affiliation, race and ethnic origin.The company has taken a more proactive approach regarding content.