Facebook users became much more protective about who sees sensitive information about them, even as they were urged to share more about themselves on the social network, according to an unusual seven-year study by researchers at Carnegie Mellon University.  The study followed the privacy settings of roughly 5,000 Facebook users who were part of the university network on Facebook between 2005 and 2011. It is among the first longitudinal efforts aimed at gauging how Facebook users try to protect their information.  The study showed how over those years, Facebook made changes that elicited increasing amounts of data. For example, the social network tripled the data fields its users could fill out. It introduced Timeline in 2011, encouraging users to fill in much more personal history, including whether they were expecting a baby or had acquired a new car. Its diverse applications offered users the opportunity to share what news articles and books they read. And it let them “tag” one another, effectively allowing one user to post information about a Facebook “friend.”  But even as Facebook encouraged more sharing, users became less likely to reveal to strangers certain pieces of sensitive, fine-grained personal information like dates of birth and what high school they attended, the survey found. There was a similar decline in users revealing their phone numbers and instant-messaging addresses to others in the university network who were not their Facebook “friends.”  Then, between late 2009 and late 2010, the data found a swift, marked turnaround, as if users had suddenly decided to become more public about what they shared. The more likely explanation, the researchers said, was that the company tweaked its privacy interface in December 2009. The changes proved confusing to many users, who made public some information they may have intended to keep private.  Eventually, Facebook’s changes to its privacy settings attracted the attention of government regulators. In 2011, the company agreed to let the Federal Trade Commission carry out annual audits of its privacy policies for 20 years.  The research paper, written by Alessandro Acquisti, Ralph Gross and Fred Stutzman, is unusual in that it followed the privacy practices of a set of users over an extended period. It did not receive any financing from Facebook or its business rivals.  It is consistent with other studies, including by the Pew Internet Center, which has found that Facebook users increasingly calibrated whom they were sharing with on the social network. Between 2009 and 2011, a growing number of those surveyed by Pew said they had deleted comments and removed someone from among their Facebook “friends.” Pew documented anxiety among parents of teenagers in particular: About a third of parents surveyed said they had helped their children adjust their privacy settings.  And earlier this year, Pew reported that 61 percent of Facebook users surveyed said they had taken a break from the social network. Among the main reasons, they said, was a lack of time to prune their privacy settings.  Data is at the core of Facebook’s business. The company uses aggregated data to show targeted advertisements. It has in recent years offered users a way to control who sees a particular post or picture, as they are about to share it.  The company does not share information about its users’ privacy practices. Responding to a request for comment about the research paper, a Facebook spokesman, Andrew Noyes, said in an e-mailed statement: “Independent research has verified that the vast majority of the people on Facebook are engaging with and using our straightforward and powerful privacy tools — allowing them to control what they’re sharing, and with whom they’re sharing.”  The Carnegie Mellon academics noted that their study focused on a subset of Facebook users, mostly undergraduates who had signed up for Facebook as early as 2005 when it was restricted to college students.  They concluded that “over time, the amount and scope of personal information that Facebook users have revealed to friends’ profiles seems to have markedly increased — and thus, so have disclosures to Facebook itself, third-party apps, and (indirectly) advertisers.”  Hence, the paper is entitled “Silent Listeners: The Evolution of Privacy and Disclosures on Facebook.”
Facebook users in one university network have become more wary of revealing sensitive personal information to the public even as they seem to be revealing much more about themselves to Facebook and its third-party business partners, an academic paper concludes.