As Facebook sought to become the world's dominant social media service, it struck agreements allowing phone and other device makers access to vast amounts of its users' personal information. Facebook has reached data-sharing partnerships with at least 60 device makers - including Apple, Amazon, BlackBerry, Microsoft and Samsung. The partnerships ... raise concerns about the company's privacy protections and compliance with a 2011 consent decree with the Federal Trade Commission. Facebook allowed the device companies access to the data of users' friends without their explicit consent, even after declaring that it would no longer share such information with outsiders. Some device makers could retrieve personal information even from users' friends who believed they had barred any sharing. In interviews, several former Facebook software engineers and security experts said they were surprised at the ability to override sharing restrictions. It's like having door locks installed, only to find out that the locksmith also gave keys to all of his friends so they can come in and rifle through your stuff without having to ask you for permission," said Ashkan Soltani, a research and privacy consultant who formerly served as the F.T.C.'s chief technologist.