Chilling Effects: Online Surveillance and Wikipedia Use by Jon Penney :: SSRN

Chilling Effects: Online Surveillance and Wikipedia Use

66 Pages Posted: 27 Apr 2016 Last revised: 8 Sep 2016

Jon Penney

University of Oxford - Oxford Internet Institute; Citizen Lab, University of Toronto; Harvard University - Berkman Klein Center for Internet & Society; Dalhousie University - Schulich School of Law

Date Written: 2016


This article discusses the results of the first empirical study providing evidence of regulatory “chilling effects” of Wikipedia users associated with online government surveillance. The study explores how traffic to Wikipedia articles on topics that raise privacy concerns for Wikipedia users decreased after the widespread publicity about NSA/PRISM surveillance revelations in June 2013. Using an interdisciplinary research design, the study tests the hypothesis, based on chilling effects theory, that traffic to privacy-sensitive Wikipedia articles reduced after the mass surveillance revelations. The Article finds not only a statistically significant immediate decline in traffic for these Wikipedia articles after June 2013, but also a change in the overall secular trend in the view count traffic, suggesting not only immediate but also long-term chilling effects resulting from the NSA/PRISM online surveillance revelations. These, and other results from the case study, not only offer compelling evidence for chilling effects associated with online surveillance, but also offer important insights about how we should understand such chilling effects and their scope, including how they interact with other dramatic or significant events (like war and conflict) and their broader implications for privacy, U.S. constitutional litigation, and the health of democratic society. This study is among the first to demonstrate — using either Wikipedia data or web traffic data more generally — how government surveillance and similar actions may impact online activities, including access to information and knowledge online.

Keywords: chilling effects, surveillance, NSA, government, Snowden, online monitoring, online surveillance, privacy, freedom of expression, freedom of speech, online rights, Wikipedia, Wikimedia, constitutional litigation, standing, empirical legal studies

JEL Classification: K19, K40, K41, K42, K49

Suggested Citation

Penney, Jon, Chilling Effects: Online Surveillance and Wikipedia Use (2016). Berkeley Technology Law Journal, Vol. 31, No. 1, p. 117, 2016. Available at SSRN:

Jonathon Penney (Contact Author)

University of Oxford - Oxford Internet Institute ( email )

1 St. Giles
University of Oxford
Oxford OX1 3PG Oxfordshire, Oxfordshire OX1 3JS
United Kingdom

Citizen Lab, University of Toronto ( email )

Munk School of Global Affairs
University of Toronto
Toronto, Ontario M5S 3K7

Harvard University - Berkman Klein Center for Internet & Society ( email )

Harvard Law School
23 Everett, 2nd Floor
Cambridge, MA Nova Scotia 02138

Dalhousie University - Schulich School of Law ( email )

6061 University Avenue
PO Box 15000
Halifax, Nova Scotia B3H 4R2

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