Privacy
Week 5
Lorrie Cranor • http://lorrie.cranor.org/
1
What is privacy?
Lorrie Cranor • http://lorrie.cranor.org/
2
What does privacy mean to you?
How would you define privacy?
What does it meant to you for something to
be private?
Lorrie Cranor • http://lorrie.cranor.org/
3
Concept versus right
Privacy as concept
• What is it
• How and why it is valued
Privacy as right
• How it is (or should be) protected
 By law
 By policy
 By technology
Lorrie Cranor • http://lorrie.cranor.org/
4
Hard to define
“Privacy is a value so complex, so
entangled in competing and contradictory
dimensions, so engorged with various and
distinct meanings, that I sometimes despair
whether it can be usefully addressed at all.”
Robert C. Post, Three Concepts of Privacy,
89 Geo. L.J. 2087 (2001).
Lorrie Cranor • http://lorrie.cranor.org/
5
Some definitions from the literature
Personhood
Intimacy
Secrecy
Contextual integrity
Limited access to the self
Control over information
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6
Limited access to self
“the right to be let alone”
- Samuel D. Warren and Louis D. Brandeis,
The Right to Privacy,
4 Harv. L. Rev. 193 (1890)
“Being alone.”
- Shane (age 4)
“our concern over
our accessibility to others: the
extent to which we are known
to others, the extent to which
others have physical access to
us, and the extent to which we
are the subject of others
attention.
- Ruth Gavison, “Privacy and the Limits of the
Law,” Yale Law Journal 89 (1980)
Lorrie Cranor • http://lorrie.cranor.org/
7
Control over information
“Privacy is the claim of individuals, groups or
institutions to determine for themselves when,
how, and to what extent information about them is
communicated to others.”
“…each individual is continually engaged in a
personal adjustment process in which he
balances the desire for privacy with the desire for
disclosure and communication….”
Alan Westin, Privacy and Freedom, 1967
Lorrie Cranor • http://lorrie.cranor.org/
8
Realizing limited access and control
Limited access
• Laws to prohibit or limit collection, disclosure,
contact
• Technology to facilitate anonymous
transactions, minimize disclosure
Control
• Laws to mandate choice (opt-in/opt-out)
• Technology to facilitate informed consent, keep
track of and enforce privacy preferences
Lorrie Cranor • http://lorrie.cranor.org/
9
Westin’s four states of privacy
 Solitude
• individual separated from the group and freed from the
observation of other persons
 Intimacy
• individual is part of a small unit
 Anonymity
• individual in public but still seeks and finds freedom
from identification and surveillance
 Reserve
• the creation of a psychological barrier against
unwanted intrusion - holding back communication
Lorrie Cranor • http://lorrie.cranor.org/
10
Britney Spears:
“We just need privacy”
“You have to realize that
we're people and that we
need, we just need privacy
and we need our respect,
and those are things that
you have to have as a
human being.”
— Britney Spears
15 June 2006
NBC Dateline
http://www.cnn.com/2006/SHOWBIZ/Music/06/15/people.spears.reut/index.html
Lorrie Cranor • http://lorrie.cranor.org/
11
Only a
goldfish can
live without
privacy…
Is this true?
Can humans
live without
privacy?
Privacy as animal instinct
Is privacy necessary for species survival?
Eagles eating a deer carcass http://www.learner.org/jnorth/tm/eagle/CaptureE63.html
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13
Privacy laws and self-regulation
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14
Terminology
 Data subject
• The person whose data is collected
 Data controller
• The entity responsible for collected data
 Primary use of personal information (primary
purpose)
• Using information for the purposes intended by the
data subjects when they provided the information
 Secondary use of personal information
(secondary purpose)
• Using information for purposes that go beyond the
primary purpose
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15
OECD fair information principles
http://www.datenschutzberlin.de/gesetze/internat/ben.htm
 Collection limitation
 Data quality
 Purpose specification
 Use limitation
 Security safeguards
 Openness
 Individual participation
 Accountability
Lorrie Cranor • http://lorrie.cranor.org/
16
US FTC simplified principles
 Notice and disclosure
 Choice and consent
 Data security
 Data quality and access
 Recourse and remedies
US Federal Trade Commission, Privacy Online: A Report to
Congress (June 1998),
http://www.ftc.gov/reports/privacy3/
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17
Privacy laws around the world
 Privacy laws and regulations vary widely throughout the
world
 US has mostly sector-specific laws, with relatively minimal
protections - often referred to as “patchwork quilt”
• Federal Trade Commission has jurisdiction over fraud and
deceptive practices
• Federal Communications Commission regulates
telecommunications
 European Data Protection Directive requires all European
Union countries to adopt similar comprehensive privacy
laws that recognize privacy as fundamental human right
• Privacy commissions in each country (some countries have
national and state commissions)
• Many European companies non-compliant with privacy laws (2002
study found majority of UK web sites non-compliant)
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18
US law basics
Constitutional law governs the rights of
individuals with respect to the government
Tort law governs disputes between private
individuals or other private entities
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19
US Constitution
 No explicit privacy right, but a zone of privacy recognized in its
penumbras, including
•
•
•
•
•
1st amendment (right of association)
3rd amendment (prohibits quartering of soldiers in homes)
4th amendment (prohibits unreasonable search and seizure)
5th amendment (no self-incrimination)
9th amendment (all other rights retained by the people)
 Penumbra: “fringe at the edge of a
deep shadow create by an object
standing in the light”
(Smith 2000, p. 258, citing Justice William O. Douglas in Griswold v. Connecticut)
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20
Federal statutes and state laws
 Federal statutes
• Tend to be narrowly focused
 State law
• State constitutions may recognize explicit right to
privacy (Georgia, Hawaii)
• State statutes and common (tort) law
• Local laws and regulations (for example: ordinances
on soliciting anonymously)
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21
Four aspects of privacy tort
 You can sue for damages for the following torts
(Smith 2000, p. 232-233)
• Disclosure of truly intimate facts
 May be truthful
 Disclosure must be widespread, and offensive or objectionable to a
person of ordinary sensibilities
 Must not be newsworthy or legitimate public interest
• False light
 Personal information or picture published out of context
• Misappropriation (or right of publicity)
 Commercial use of name or face without permission
• Intrusion into a person’s solitude
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22
Some US privacy laws
 Bank Secrecy Act, 1970
 Fair Credit Reporting Act, 1971
 Privacy Act, 1974
 Right to Financial Privacy Act, 1978
 Cable TV Privacy Act, 1984
 Video Privacy Protection Act, 1988
 Family Educational Right to Privacy Act, 1993
 Electronic Communications Privacy Act, 1994
 Freedom of Information Act, 1966, 1991, 1996
Lorrie Cranor • http://lorrie.cranor.org/
23
US law – recent additions
 HIPAA (Health Insurance Portability and
Accountability Act, 1996)
• When implemented, will protect medical records and
other individually identifiable health information
 COPPA (Children‘s Online Privacy Protection Act,
1998)
• Web sites that target children must obtain parental
consent before collecting personal information from
children under the age of 13
 GLB (Gramm-Leach-Bliley-Act, 1999)
• Requires privacy policy disclosure and opt-out
mechanisms from financial service institutions
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24
Safe harbor
 Membership
• US companies self-certify adherence to requirements
• Dept. of Commerce maintains signatory list
http://www.export.gov/safeharbor/
• Signatories must provide
 notice of data collected, purposes, and recipients
 choice of opt-out of 3rd-party transfers, opt-in for sensitive
data
 access rights to delete or edit inaccurate information
 security for storage of collected data
 enforcement mechanisms for individual complaints
 Approved July 26, 2000 by EU
• reserves right to renegotiate if remedies for EU citizens
prove to be inadequate
Lorrie Cranor • http://lorrie.cranor.org/
25
Voluntary privacy guidelines
 Direct Marketing Association Privacy Promise
http://www.thedma.org/library/
privacy/privacypromise.shtml
 Network Advertising Initiative Principles
http://www.networkadvertising.org/
 CTIA Location-based privacy guidelines
http://www.wowcom.com/news/press/body.cfm?record_id=907
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26
Lorrie Cranor • http://lorrie.cranor.org/
27
Chief privacy officers
 Companies are increasingly appointing CPOs to
have a central point of contact for privacy
concerns
 Role of CPO varies in each company
•
•
•
•
Draft privacy policy
Respond to customer concerns
Educate employees about company privacy policy
Review new products and services for compliance with
privacy policy
• Develop new initiatives to keep company out front on
privacy issue
• Monitor pending privacy legislation
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28
Seal programs
 TRUSTe – http://www.truste.org
 BBBOnline – http://www.bbbonline.org
 CPA WebTrust –
http://www.cpawebtrust.org/
 Japanese Privacy Mark
http://privacymark.org/
Lorrie Cranor • http://lorrie.cranor.org/
29
Seal program problems
Certify only compliance with stated policy
• Limited ability to detect non-compliance
Minimal privacy requirements
Don’t address privacy issues that go
beyond the web site
Nonetheless, reporting requirements are
forcing licensees to review their own
policies and practices and think carefully
before introducing policy changes
Lorrie Cranor • http://lorrie.cranor.org/
30
Privacy policies
Policies let consumers know about site’s
privacy practices
Consumers can then decide whether or not
practices are acceptable, when to opt-in or
opt-out, and who to do business with
The presence of privacy policies increases
consumer trust
What are some problems with privacy policies?
Lorrie Cranor • http://lorrie.cranor.org/
31
Privacy policy problems
BUT policies are often
•
•
•
•
difficult to understand
hard to find
take a long time to read
change without notice
Lorrie Cranor • http://lorrie.cranor.org/
32
Privacy policy components
 Identification of site, scope, contact
info
 Security assurances
 Types of information collected
 Children’s privacy
•
Including information about cookies
 How information is used
 Conditions under which information
might be shared
 Information about opt-in/opt-out
 Information about access
 Information about data retention
policies
There is lots of information
to convey -- but policy
should be brief and
easy-to-read too!
 Information about seal programs
What is opt-in? What is opt-out?
Lorrie Cranor • http://lorrie.cranor.org/
33
How are online privacy concerns
different from offline privacy
concerns?
Lorrie Cranor • http://lorrie.cranor.org/
34
Web privacy concerns
 Data is often collected silently
• Web allows large quantities of data to be collected inexpensively
and unobtrusively
 Data from multiple sources may be merged
• Non-identifiable information can become identifiable when merged
 Data collected for business purposes may be used in civil
and criminal proceedings
 Users given no meaningful choice
• Few sites offer alternatives
Lorrie Cranor • http://lorrie.cranor.org/
35
Browser Chatter
 Browsers chatter
about
• IP address, domain
name, organization,
• Referring page
• Platform: O/S, browser
• What information is
requested
 URLs and search terms
• Cookies
Lorrie Cranor • http://lorrie.cranor.org/
 To anyone who might
be listening
• End servers
• System administrators
• Internet Service
Providers
• Other third parties
 Advertising networks
• Anyone who might
subpoena log files later
36
Typical HTTP request with cookie
GET /retail/searchresults.asp?qu=beer HTTP/1.0
Referer: http://www.us.buy.com/default.asp
User-Agent: Mozilla/4.75 [en] (X11; U; NetBSD 1.5_ALPHA
i386)
Host: www.us.buy.com
Accept: image/gif, image/jpeg, image/pjpeg, */*
Accept-Language: en
Cookie: buycountry=us; dcLocName=Basket;
dcCatID=6773; dcLocID=6773; dcAd=buybasket; loc=;
parentLocName=Basket; parentLoc=6773;
ShopperManager%2F=ShopperManager%2F=66FUQU
LL0QBT8MMTVSC5MMNKBJFWDVH7; Store=107;
Category=0
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37
Referer log problems
GET methods result in values in URL
These URLs are sent in the referer
header to next host
Example:
http://www.merchant.com/cgi_bin/o
rder?name=Tom+Jones&address=here
+there&credit+card=234876923234&
PIN=1234&->index.html
Access log example
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38
Cookies
What are cookies?
What are people concerned about cookies?
What useful purposes do cookies serve?
Lorrie Cranor • http://lorrie.cranor.org/
39
Cookies 101
Cookies can be useful
• Used like a staple to attach multiple parts of a
form together
• Used to identify you when you return to a web
site so you don’t have to remember a
password
• Used to help web sites understand how people
use them
Cookies can do unexpected things
• Used to profile users and track their activities,
especially across web sites
Lorrie Cranor • http://lorrie.cranor.org/
40
How cookies work – the basics
 A cookie stores a small string of characters
 A web site asks your browser to “set” a cookie
 Whenever you return to that site your browser sends the
cookie back automatically
Please store
cookie xyzzy
site
Here is cookie
xyzzy
browser
First visit to site
Lorrie Cranor • http://lorrie.cranor.org/
site
browser
Later visits
41
How cookies work – advanced
 Cookies are only sent back to
the “site” that set them – but
this may be any host in domain
• Sites setting cookies indicate
path, domain, and expiration
for cookies
Send
me with
any
request
to x.com
until
2008
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Send me
with requests
for
index.html
on y.x.com
for this
session only
 Cookies can store user info or a
database key that is used to
look up user info – either way
the cookie enables info to be
linked to the current browsing
session
User=Joe
Email=
Joe@
x.com
Visits=13
Database
Users …
Email …
Visits …
User=4576
904309
42
Cookie terminology
 Cookie Replay – sending a cookie back to a site
 Session cookie – cookie replayed only during current
browsing session
 Persistent cookie – cookie replayed until expiration date
 First-party cookie – cookie associated with the site the
user requested
 Third-party cookie – cookie associated with an image, ad,
frame, or other content from a site with a different domain
name that is embedded in the site the user requested
• Browser interprets third-party cookie based on domain name,
even if both domains are owned by the same company
Lorrie Cranor • http://lorrie.cranor.org/
43
Web bugs
 Invisible “images” (1-by-1 pixels, transparent) embedded
in web pages and cause referer info and cookies to be
transferred
 Also called web beacons, clear gifs, tracker gifs,etc.
 Work just like banner ads from ad networks, but you can’t
see them unless you look at the code behind a web page
 Also embedded in HTML formatted email messages, MS
Word documents, etc.
 For software to detect web bugs see:
http://www.bugnosis.org
Lorrie Cranor • http://lorrie.cranor.org/
44
How data can be linked
 Every time the same cookie is replayed to a site,
the site may add information to the record
associated with that cookie
•
•
•
•
Number of times you visit a link, time, date
What page you visit
What page you visited last
Information you type into a web form
 If multiple cookies are replayed together, they are
usually logged together, effectively linking their
data
• Narrow scoped cookie might get logged with broad
scoped cookie
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45
Ad networks
search for
medical
information
buy CD
set cookie
replay cookie
Ad
Ad
Search Service
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Ad company
can get your
name and
address from
CD order and
link them to
your search
CD Store
46
What ad networks may know…
 Personal data:
• Email address
• Full name
• Mailing address (street,
city, state, and Zip
code)
• Phone number
 Transactional data:
• Details of plane trips
• Search phrases used
at search engines
• Health conditions
“It was not necessary for me to click on the banner ads
for information to be sent to DoubleClick servers.”
– Richard M. Smith
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47
Online and offline merging
 In November 1999, DoubleClick
purchased Abacus Direct, a
company possessing detailed consumer profiles on more
than 90% of US households.
 In mid-February 2000 DoubleClick announced plans to
merge “anonymous” online data with personal information
obtained from offline databases
 By the first week in March 2000 the plans were put on
hold
• Stock dropped from $125 (12/99) to $80 (03/00)
Lorrie Cranor • http://lorrie.cranor.org/
48
Offline data goes online…
The
Cranor
family’s 25
most
frequent
grocery
purchases
(sorted by
nutritional
value)!
Lorrie Cranor • http://lorrie.cranor.org/
49
Subpoenas
Data on online activities is increasingly of
interest in civil and criminal cases
The only way to avoid subpoenas is to not
have data
In the US, your files on your computer in
your home have much greater legal
protection that your files stored on a server
on the network
Lorrie Cranor • http://lorrie.cranor.org/
50
P3P: Introduction
Original Idea behind P3P
 A framework for automated privacy
discussions
• Web sites disclose their privacy practices in
standard machine-readable formats
• Web browsers automatically retrieve P3P
privacy policies and compare them to users’
privacy preferences
• Sites and browsers can then negotiate about
privacy terms
Lorrie Cranor • http://lorrie.cranor.org/
52
P3P: Introduction
P3P history
 Idea discussed at November 1995 FTC meeting
 Ad Hoc “Internet Privacy Working Group” convened to
discuss the idea in Fall 1996
 W3C began working on P3P in Summer 1997
• Several working groups chartered with dozens of participants from
industry, non-profits, academia, government
• Numerous public working drafts issued, and feedback resulted in
many changes
• Early ideas about negotiation and agreement ultimately removed
• Automatic data transfer added and then removed
• Patent issue stalled progress, but ultimately became non-issue
 P3P issued as official W3C Recommendation on April 16,
2002
• http://www.w3.org/TR/P3P/
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53
P3P: Introduction
P3P1.0 – A first step
Offers an easy way for web sites to
communicate about their privacy policies in
a standard machine-readable format
• Can be deployed using existing web servers
This will enable the development of tools
that:
• Provide snapshots of sites’ policies
• Compare policies with user preferences
• Alert and advise the user
Lorrie Cranor • http://lorrie.cranor.org/
54
P3P: Introduction
The basics
 P3P provides a standard XML format that web
sites use to encode their privacy policies
 Sites also provide XML “policy reference files” to
indicate which policy applies to which part of the
site
 Sites can optionally provide a “compact policy” by
configuring their servers to issue a special P3P
header when cookies are set
 No special server software required
 User software to read P3P policies called a “P3P
user agent”
Lorrie Cranor • http://lorrie.cranor.org/
55
P3P: Enabling your web site – overview and options
What’s in a P3P policy?
 Name and contact information for site
 The kind of access provided
 Mechanisms for resolving privacy disputes
 The kinds of data collected
 How collected data is used, and whether
individuals can opt-in or opt-out of any of these
uses
 Whether/when data may be shared and whether
there is opt-in or opt-out
 Data retention policy
Lorrie Cranor • http://lorrie.cranor.org/
56
P3P/XML encoding
Statement
P3P version
<POLICIES xmlns="http://www.w3.org/2002/01/P3Pv1">
<POLICY discuri="http://p3pbook.com/privacy.html"
Location of
name="policy">
human-readable
P3P policy name
<ENTITY>
<DATA-GROUP>
privacy policy
<DATA
Site’s
ref="#business.contact-info.online.email">privacy@p3pbook.com
name
</DATA>
and
<DATA
ref="#business.contact-info.online.uri">http://p3pbook.com/
contact
</DATA>
info
<DATA ref="#business.name">Web Privacy With P3P</DATA>
</DATA-GROUP>
Access disclosure
</ENTITY>
Human-readable
<ACCESS><nonident/></ACCESS>
explanation
<STATEMENT>
<CONSEQUENCE>We keep standard web server logs.</CONSEQUENCE>
<PURPOSE><admin/><current/><develop/></PURPOSE>
How data may
<RECIPIENT><ours/></RECIPIENT>
be used
<RETENTION><indefinitely/></RETENTION>
<DATA-GROUP>
Data recipients
<DATA ref="#dynamic.clickstream"/>
<DATA ref="#dynamic.http"/>
Data retention policy
</DATA-GROUP>
</STATEMENT>
Types of data collected
</POLICY>
</POLICIES>
P3P: Introduction
P3P1.0 Spec Defines
 A standard vocabulary for describing set of uses,
recipients, data categories, and other privacy
disclosures
 A standard schema for data a Web site may wish
to collect (base data schema)
 An XML format for expressing a privacy policy in
a machine readable way
 A means of associating privacy policies with Web
pages or sites
 A protocol for transporting P3P policies over
HTTP
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58
P3P: Introduction
A simple HTTP transaction
GET /index.html HTTP/1.1
Host: www.att.com
. . . Request web page
Web
Server
HTTP/1.1 200 OK
Content-Type: text/html
. . . Send web page
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59
P3P: Introduction
… with P3P 1.0 added
GET /w3c/p3p.xml HTTP/1.1
Host: www.att.com
Request Policy Reference File
Web
Server
Send Policy Reference File
Request P3P Policy
Send P3P Policy
GET /index.html HTTP/1.1
Host: www.att.com
. . . Request web page
HTTP/1.1 200 OK
Content-Type: text/html
. . . Send web page
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60
P3P: Introduction
Transparency
 P3P clients can check
a privacy policy each
time it changes
http://www.att.com/accessatt/
 P3P clients can check
privacy policies on all
objects in a web page,
including ads and
invisible images
http://adforce.imgis.com/?adlink|2|68523|1|146|ADFORCE
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61
P3P: Introduction
P3P in IE6
Automatic processing of
compact policies only;
third-party cookies without
compact policies blocked by
default
Privacy icon on status bar
indicates that a cookie has
been blocked – pop-up appears
the first time the privacy icon
appears
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62
P3P: Introduction
Users can click on
privacy icon for
list of cookies;
privacy summaries
are available at
sites that are
P3P-enabled
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63
P3P: Introduction
Privacy summary
report is
generated
automatically
from full P3P policy
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64
P3P: Introduction
P3P in Netscape 7
Preview version similar to IE6,
focusing, on cookies; cookies
without compact policies (both
first-party and third-party)
are “flagged” rather than
blocked by default
Indicates flagged cookie
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65
P3P: Introduction
Users can view English
translation of (part of)
compact policy in Cookie
Manager
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66
P3P: Introduction
A policy summary can be
generated automatically
from full P3P policy
Lorrie Cranor • http://lorrie.cranor.org/
67
Privacy Bird
 Free download of beta from
http://privacybird.org/
• Origninally developed at AT&T Labs
• Released as open source
 “Browser helper object” for IE6
 Reads P3P policies at all
P3P-enabled sites automatically
 Bird icon at top of browser window indicates whether site
matches user’s privacy preferences
 Clicking on bird icon gives more information
Lorrie Cranor • http://lorrie.cranor.org/
68
Chirping bird is privacy indicator
Red bird indicates mismatch
Check embedded content too
Privacy settings
Example:
Sending flowers
Privacy Finder
 Prototype developed at AT&T Labs, improved and
deployed by CUPS
 Uses Google or Yahoo! API to retrieve search
results
 Checks each result for P3P policy
 Evaluates P3P policy against user’s preferences
 Reorders search results
 Composes search result page with privacy
annotations next to each P3P-enabled result
 Users can retrieve “Privacy Report” similar to
Privacy Bird policy summary
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Demo
Evaluating Privacy Finder
 Have enough sites adopted P3P for Privacy Finder to be
useful?
• S. Egelman, L. Cranor, and A. Chowdhury. An Analysis of P3P-Enabled
Web Sites among Top-20 Search Results. Proceedings of the Eighth
International Conference on Electronic Commerce August 14-16, 2006,
Fredericton, New Brunswick, Canada.
 Will the prominent display of privacy information cause
consumers to take privacy into account when making
online purchasing decisions?
• J. Gideon, S. Egelman, L. Cranor, and A. Acquisti. Power Strips,
Prophylactics, and Privacy, Oh My! In Proceedings of the 2006
Symposium On Usable Privacy and Security, 12-14 July 2006, Pittsburgh,
PA.
• J. Tsai, S. Egelman, L. Cranor, and A. Acquisti. The Effect of Online
Privacy Information on Purchasing Behavior: An Experimental Study.
Workshop on the Economics of Information Security, June 7-8, 2007,
Pittsburgh, PA.
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P3P adoption study
 Compiled two lists of search terms:
• Typical: 20,000 terms sampled from week of AOL user
queries
• Ecommerce: 940 terms screen scraped from Froogle
front page
 Submitted search terms to Google, Yahoo!, and
AOL search engines and collected top 20 results
for each term
 Checked each result for P3P policy and
evaluated policies
 Checked for P3P policies on 30,000 domains
most clicked on by AOL search engine users
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Frequency of P3P-enabled hits
 P3P-enabled top-20 search results
• Typical search terms: 10%
• E-commerce search terms: 21%
 Searches that return at least one P3P-enabled results
• In top 10 results: 68%
• In top 20 results: 83%
 AOL users will find sites with “good” privacy policies in
first 2 pages of results about 1/3 of the time
 We’ve also collected data about types of privacy
practices, types of sites that have adopted P3P,
and errors in P3P policies
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Results: Most popular P3P policies
Typical Terms

Ecommerce Terms
 http://privacy.yahoo.com/
 
http://privacy.yahoo.com/
 http://about.com/
 http://about.com/
 http://privacy.msn.com/
 http://www.bizrate.com/
 http://disney.go.com/
 http://www0.shopping.com/
 http://images.rootsweb.com/
 http://www.shopping.com/
 http://adserver.ign.com/
 http://www.pricegrabber.com/
 http://www.nlm.nih.gov/
 http://www.cpsc.gov/
 http://www.bizrate.com/
 http://www.overstock.com/
 http://www.superpages.com/
 http://www.cooking.com/
 http://www.shopping.com/
 http://www.altrec.com/
Lorrie Cranor • http://lorrie.cranor.org/
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Does Privacy Finder influence purchases?
 Online shopping studies
• Pay participants to make online purchases with their
own credit cards
• Some use Privacy Finder and some use generic
search engine
• Experiment with privacy sensitivity of purchase and
price sensitivity
• Lab studies
 Study of college students purchasing power strips and
condoms, no price incentive (reimburse cost)
 Study of Pittsburgh residents purchasing batteries and sex
toys, with price incentive (keep the change)
 Larger study testing additional conditions planned
 Privacy Finder field study planned
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82
Lab study design
16 participants in each condition
• Condition 1: No information
• Condition 2: Irrelevant information
• Condition 3: Privacy information
Products
• Non-privacy Sensitive - batteries
• Privacy sensitive - sex toy
Participants paid fixed amount and told to
“keep the change”
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Privacy information condition
Privacy premium:
$0.69 4.8%
Irrelevant information condition
No information condition
Results
% Purchases by Level of Privacy
No Information
Handicap
Privacy
100%
90%
% Purchases
80%
70%
60%
50%
40%
30%
20%
10%
0%
None
Low
Med.
High
None
Batteries
Low
Med.
Sex Toy
Level of Privacy
High
Conclusions
Accessible privacy information affects
consumer behavior
Consumers willing to pay for better privacy
Privacy Finder helps users make privacy
informed decisions
Lorrie Cranor • http://lorrie.cranor.org/
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P3P: Introduction
Why web sites adopt P3P
 Demonstrate corporate leadership on privacy
issues
• Show customers they respect their privacy
• Demonstrate to regulators that industry is taking
voluntary steps to address consumer privacy concerns
 Distinguish brand as privacy friendly
 Prevent IE6 from blocking their cookies
 Anticipation that consumers will soon come to
expect P3P on all web sites
 Individuals who run sites value personal privacy
Lorrie Cranor • http://lorrie.cranor.org/
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P3P: Introduction
P3P early adopters
 News and information sites – CNET, About.com,
BusinessWeek
 Search engines – Yahoo, Lycos
 Ad networks – DoubleClick, Avenue A
 Telecom companies – AT&T
 Financial institutions – Fidelity
 Computer hardware and software vendors – IBM, Dell,
Microsoft, McAfee
 Retail stores – Fortunoff, Ritz Camera
 Government agencies – FTC, Dept. of Commerce,
Ontario Information and Privacy Commissioner
 Non-profits - CDT
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P3P: The future
Impacts
Some companies that P3P-enable think
about privacy in new ways and change
their practices
• Systematic assessment of privacy practices
• Concrete disclosures – less wiggle room
• Disclosures about areas previously not
discussed in privacy policy
Hopefully we will see greater transparency,
more informed consumers, and ultimately
better privacy policies
Lorrie Cranor • http://lorrie.cranor.org/
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