A seven-year Carnegie Mellon University study of Facebook has found evidence of three contrasting trends in the amount of information Facebook users disclosed over time: decreasing public disclosures; abrupt changes in disclosure due to interface and policy changes; and increasing private disclosures.
The 2005-2011 study, which appears in The Journal of Privacy and Confidentiality is the first longitudinal study to document how privacy and disclosure evolve on social network sites over an extended period of time. Researchers found that from 2005-2009, Facebook users displayed more privacy-seeking behavior, progressively decreasing the amount of personal data shared with the public.
This trend abruptly reversed between 2009 and 2010, when changes implemented by Facebook, such as modifications to its user interface and default settings, led to a significant increase in the public sharing of various types of personal information. The study also found that, over time, the amount and scope of personal information that Facebook users revealed to their Facebook “friends” actually increased. As a result, users ended up increasing their personal disclosures to other entities on the network, sometimes unknowingly, including to “silent listeners” such as Facebook itself, third-party apps and advertisers.
Our analysis highlights three contrasting trends. First, over time Facebook users in our dataset exhibited increasingly privacy-seeking behavior, progressively decreasing the amount of personal data shared publicly with unconnected profiles in the same network. However, and second, changes implemented by Facebook near the end of the period of time under our observation arrested or in some cases inverted that trend. Third, the amount and scope of personal information that Facebook users revealed privately to other connected profiles actually increased over time—and because of that, so did disclosures to “silent listeners” on the network: Facebook itself, third-party apps, and (indirectly) advertisers. These findings highlight the tension between privacy choices as expressions of individual subjective preferences, and the role of the environment in shaping those choices.
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Journal of Privacy and Confidentiality
Fred Stutzman, Carnegie Mellon University
Ralph Gross, Carnegie Mellon University
Alessandro Acquisti, Carnegie Mellon University