https://www.reuters.com/article/us-eu-facebook-antitrust/facebooks-marketplace-in-eu-and-uk-antitrust-crosshairs-idUSKCN2DG0ZX >BRUSSELS/LONDON (Reuters) -Europe and Britain launched formal antitrust investigations into Facebook on Friday to determine if the world's largest social network was using customer data to unfairly compete with advertisers, in a new assault on its business model.