https://www.reuters.com/article/us-facebook-cambridge-analytica/facebooks-zuckerberg-acknowledges-mistakes-on-user-data-vows-tougher-curbs-idUSKBN1GX0OG >Facebook Inc Chief Executive Mark Zuckerberg said on Wednesday that his company made mistakes in mishandling data belonging to 50 million of its users and promised tougher steps to restrict developers access to data.