Facebook users are more protective of their personal information now than they had been in 2005.
From 2005 to 2009, Facebook users were more concerned about their privacy than they were the following year, and cut the amount of personal data they shared with the public.
Facebook modified its user interface and settings between 2009 and 2010. The changes reversed the trend when users quickly increased the amount of personal data they released to the public.
The study found that as time progressed, the number and range of personal data shown to Facebook friends increased. Users unknowingly increased the number of private information seen by unconnected profiles, known to the researchers as "silent listeners" - advertisers, third-party applications, and Facebook itself.
The study used data from 5,076 Facebook users, and the researchers said it is the first study to use data from the social network's early days in 2005.
Mark Zuckerberg and his colleagues founded Facebook, previously known as Thefacebook.com, in February 2004 from a Harvard University dormitory room. They ran tests across multiple campuses in the United States that year.
Co-author Alessandro Acquisti, associate professor of Information Technology and Public Policy at CMU, said their findings show the struggle between a Facebook user's choice in privacy and the social network's part in shaping the user's preferences.
Co-author Fred Stutzman said their findings highlight the demanding situation social network users encounter when they try to oversee online privacy, the ability of social media providers to alter their activities related to privacy and disclosure, and the technical aspects to address consumers' online privacy conerns.
Co-author Ralph Gross said access to settings that help users find the personal information seen by other users could increase the feeling of control. However, sense of control on personal data and mismanagement of attention are connected to the rise in disclosures of sensitive data to complete strangers.
The 2005-2011 study entitled "Silent Listeners: The Evolution of Privacy and Disclosure on Facebook" (PDF), found in The Journal of Privacy and Confidentiality, is the first long-term written account about how privacy and disclosure develop on social networks over an extended period.