Users logging on this week are presented with a new screen that they must engage with before going on to use the site. It asks users to update their privacy preferences in the light of the site's "new, simplified privacy settings".
The default choices made on behalf of users have caused controversy, though. If users accept Facebook's pre-selected options they will make details such as details of their family, relationships and employer available to the whole internet. They would also make their birthdays and religious views available to any Facebook user who is a friend with one of their friends, and their phone numbers, physical addresses and email addresses available to all their friends.
Such settings are likely to make most people's personal information far more public than their existing settings. Though users can opt to keep their previous settings, privacy activists worry that many will accept Facebook's recommendations.
"The privacy 'transition tool' that guides users through the configuration will 'recommend' – preselect by default – the setting to share the content they post to Facebook, such as status messages and wall posts, with everyone on the internet, even though the default privacy level that those users had accepted previously was limited to 'Your Networks and Friends' on Facebook," said Kevin Bankston of digital rights lobby group the Electronic Frontier Foundation (EFF).
"These new 'privacy' changes are clearly intended to push Facebook users to publicly share even more information than before. Even worse, the changes will actually reduce the amount of control that users have over some of their personal data," he said. Bankston said that the changes create "new and serious privacy problems".
"You'll be asked to make choices about who can see the various parts of your profile and the posts you create," said a Facebook statement explaining the new process. "If you've ever chosen to restrict access to parts of your profile, we'll be recommending that you keep those more restrictive settings. If you've never done this, we'll be making recommendations based on how lots of people are sharing information today."
There have also been concerns about some information that users will no longer be able to restrict access to.
"With these changes, a limited set of basic information that helps your friends find you will be made publicly available. This information is name, profile picture, gender, current city, networks, friend list, and Pages," said the Facebook statement. "The overwhelming majority of people who use Facebook already make most or all of this information available to everyone."
"Before, users were allowed to restrict access to much of that information," said the EFF's Bankston. "Now, however, those privacy options have been eliminated. For example, although you used to have the ability to prevent everyone but your friends from seeing your friends list, that old privacy setting has now been removed completely from the privacy settings page."
"These changes are especially worrisome because even something as seemingly innocuous as your list of friends can reveal a great deal about you. In September, for example, an MIT study nicknamed 'Gaydar' demonstrated that researchers could accurately predict a Facebook user's sexual orientation simply by examining the user's friends-list. This kind of data mining of social networks is a science still in its infancy; the amount of data that can be extrapolated from 'publicly available information' will only increase with time."