larger audiences—those on Snowden
and surveillance—while Wikipedia
articles about PRISM topics lost their
increased readership. Snowden’s
revelations brought few new users
to privacy-enhancing technologies;
anonymizing proxies experienced increased numbers through 2013, but
PRISM did not add to the momentum.
While Snowden himself was the only
name to consistently attract large audiences, one may argue this interest
had already separated from the erosion of privacy he had revealed.
Only longitudinal studies with high
temporal resolution are able to reveal the influence of privacy invasions
on people’s behavior. The paucity
of such studies may be explained by
the difficulty of obtaining expressive
data. I had to rely on proxies (such as
information-seeking behavior) for users’ interest in privacy that cannot be
observed directly. My selection of data
sources was partly pragmatic, aiming
for rich data providing good coverage
of the same population over an extended time.
I thus opted to focus on English-language users in the U.S.; this so-called “en-us” market is a standard
geographic filter for many consumer
services, allowing consistent scoping
across different data sets. The trade-off between narrow but good data
leads to an obvious limitation, as users
may have chosen to pose as “en-us” in
their software settings. Still, previous
internal analyses indicate their proportion is negligible. I also plan to examine the effect PRISM had (and continues to have) in various countries.
My results warrant contrasting the effect of governmental versus corporate
wrongdoing in privacy issues.
1. BITKOM (Federal Association for Information
Technology). Internetnutzer werden misstrauisch,
July 25, 2013; http://www.bitkom.org/de/
2. Dierig, C., Fuest, B., Kaiser, T., and Wisdorff, F. Die
Welt (Apr. 13, 2014); http://www.welt.de/wirtschaft/
3. DuckDuckGo. DuckDuckGo Direct queries per day
(28-day average), July 2014; https://duckduckgo.com/
4. Dumais, S., Jeffries, R., Russell, D.M., Tang, D., and
Teevan, J. Understanding user behavior through log
data and analysis. Chapter in Ways of Knowing in HCI,
Springer, New York, 2014, 349–372.
5. Gellman, B. and Poitras, L. U.S., British intelligence
mining data from nine U.S. Internet companies in
broad secret program. The Washington Post (June 7,
6. Ginsberg J. et al. Detecting influenza epidemics using
1% of all newly found online documents. And on each of the following days, “PRISM” appeared in more
than 240,000 daily new documents
on average while competing with other initiatives (such as Tempora and
XKeyScore) (see Figure 3).
Media coverage continued over
the 30 weeks following PRISM day,
with no noticeable downward trend
for PRISM (ρ = –0.00002, F-test:
p < 0.0001), surveillance (ρ = 0.0000,
p = 0.001), or Snowden (ρ = 0.0000,
p = 0.004). By the end of the study
period—week 30 following PRISM
day—the relative daily volume of documents about Snowden was 18 times
as much as on June 6, 2013.
This article covers the first longitudinal study of the privacy behaviors
of U.S. Web users as they might have
been affected by Edward Snowden’s
2013 revelations about government
surveillance and the general lack of
communications privacy. I compared
the use of privacy-enhancing technologies pre- and post-PRISM day,
using Web search and browsing activity as proxies for interest in privacy
and information-seeking behavior.
My analysis of Web search behavior
through Microsoft’s Bing search engine may have introduced a bias impossible to quantify, should it exist.
However, external evidence suggests
Bing may be more appealing to the
19, 22 meaning the small
increases I observed could still represent an overestimation.
I combined high-resolution data
from primary sources that indicate the
new public information on PRISM led
to momentarily increased interest in
privacy and protection. However, the
spike was much less than for other
news events (such as the royal baby
and the U.S. Open golf tournament). It
was also less than the increased interest following the removal of privacy-enhancing functions in Facebook, Android, and Gmail.
While media coverage of PRISM
and surveillance was elevated for the
30 weeks following PRISM day, many
privacy behaviors faded quickly. Visits to Microsoft’s corporate privacy
policy page stayed high, but only certain privacy-related webpages kept
search engine query data. Nature 457, 7232 (Feb. 19,
7. Jackson, D., Davis, S., and Johnson, K. Obama’s spy
plan includes Internet: NSA’s expansive reach revives
an unsettled and vexing 9/11 debate. USA Today
(June 7, 2013), A1.
8. Landau, S. Making sense from Snowden: What’s
significant in the NSA surveillance revelations. IEEE
Security & Privacy 11, 4 (July–Aug. 2013), 54–63.
9. Lazer, D., Kennedy, R., King, G., and Vespignani, A.
The parable of Google flu: Traps in big data analysis.
Science 343, 6176 (Mar. 14, 2014), 1203–1205.
10. Lee, T.B. Five ways to stop the NSA from spying
on you. The Washington Post (June 10, 2013),
11. Marthews, A. and Tucker, C. Government Surveillance
and Internet Search Behavior. SSRN Working Paper,
Social Science Electronic Publishing, Inc., Rochester,
N Y, 2014.
12. McCombs, M. E. and Shaw, D. L. The agenda-setting
function of mass media. Public Opinion Quarterly 36, 2
(Summer 1972), 176–187.
13. Microsoft. Bing Help, 2013; http://onlinehelp.microsoft.
14. Microsoft. Microsoft.com Privacy Statement, 2013;
15. Mozilla. anonymoX: Add-ons for Firefox, 2014; https://
16. Nakashima, E. and Markon, J. Dozens of attacks foiled,
NSA says. Washington Post (June 13, 2013), A1.
17. Phelps, J., Gonzenbach, W., and Johnson, E. Press
coverage and public perception of direct marketing
and consumer privacy. Journal of Direct Marketing 8, 2
(Spring 1994), 9–22.
18. Preibusch, S., Kübler, D., and Beresford, A.R. Price
versus privacy: An experiment into the competitive
advantage of collecting less personal information.
Electronic Commerce Research 13, 4 (Nov. 2013),
19. Protalinski, E. Microsoft confirms Google privacy
campaign to promote Bing is aimed at Apple
Safari users. The Next Web (Sept. 20, 2012); http://
20. Rosenblatt, S. Escaping Google’s gravity: How small
search engines define success. CNET (July 11, 2013);
21. Roznowski, J.L. A content analysis of mass media
stories surrounding the consumer privacy issue,
1990–2001. Journal of Interactive Marketing 17, 2
(Apr. 2003), 52–69.
22. Stone, B. Facebook radically revamps its search
engine. Bloomberg Businessweek (Jan. 15, 2015);
23. The Tor Project, Inc. Tor Metrics Portal: Users
24. Van Grove, J. Zuckerberg: Thanks NSA, now people
trust Facebook even less. CNE T (Sept. 18, 2013);
25. Wikipedia article traffic statistics. 2013; http://stats.
Sören Preibusch ( http://preibusch.de/) is a user
experience researcher at Google, Mountain View, CA,
and was at Microsoft Research, Cambridge, U.K.,
when this article was written.
Copyright held by author.