SAN FRANCISCO • Facebook has for months been fighting the perception it does not do enough to protect people's privacy. On Thursday, the company said it had again failed to keep the information of millions of users private.
The company has asked 14 million users to review the posts they made between May 18 and May 22.
During that time, a bug in its system changed the settings on their accounts, so that users who thought they were making private updates may have made them available to the public instead.
The company said the mistake happened as it worked to redesign how it displays parts of user profiles that are always public.
Posts are public by default for new accounts, but every Facebook user can limit who sees each post by using what the company calls an "audience selector".
People can make new posts only visible to friends or sub-groups of friends, for example, by altering this default preference through their privacy settings.
But, for four days in May, the bug ignored user preferences and set the default audience for all new posts to "public", the company said.
Facebook fixed the bug on May 22, but did not restore the proper privacy settings to all posts until May 27.
"We'd like to apologise for this mistake," Ms Erin Egan, Facebook's chief privacy officer, said in a statement.
"We have fixed this issue, and starting today, we are letting everyone affected know and are asking them to review any posts they made during that time."
Trust in Facebook has fallen 66 per cent as a result of news stories in recent months, according to a survey by the Ponemon Institute, an independent research firm specialising in privacy and data protection.
Dr Norman Sadeh, co-director of Carnegie Mellon University's privacy engineering programme, said that although Facebook has survived temporary losses of trust from the public in the past, the recent scandals appeared to be taking their toll on the social media company.
Dr Sadeh also said that until Facebook and other social media companies improve their approach to privacy and develop settings that are easier to use and more aligned with what users want, "people should probably refrain from sharing too much sensitive information with these platforms".
NYTIMES, WASHINGTON POST