W3C home > Mailing lists > Public > public-tracking@w3.org > February 2012

Re: Deciding Exceptions (ISSUE-23, ISSUE-24, ISSUE-25, ISSUE-31, ISSUE-34, ISSUE-49)

From: Bryan Sullivan <blsaws@gmail.com>
Date: Wed, 01 Feb 2012 20:07:06 -0800
To: Jonathan Mayer <jmayer@stanford.edu>, "public-tracking@w3.org (public-tracking@w3.org)" <public-tracking@w3.org>
Message-ID: <CB4F43BE.107CF%blsaws@gmail.com>
Jonathan,

To balance the approach, in my view any argument against exceptions must
satisfy an equally rigorous test:

1) Specifically defined. Data that is considered privacy sensitive must be
clearly delineated, re collection, retention, and use. Any such data that
is subsequently identified by business stakeholders as important to
Business As Usual (BAU) apart from the narrow purpose of cross-site
tracking, needs a privacy sensitivity explanation that is extraordinarily
explicit.

2) No blanket restrictions. We should grant or deny an exception on the
merits of how it balances privacy and commerce, not solely upon a specific
privacy concern.

3) Compelling privacy concern. Data that is considered privacy sensitive
must be clearly delineated in terms of why it is so. A bald assertion that
collection, retention, and use of specific data should be disallowed is
inadequate. I expect privacy advocates to explain, with specificity, what
privacy concern is related to the collection, retention, and use of
specific data items. Further, I expect privacy advocates to point to
documented examples of how such data collection, retention, and use has
been at the root of publicly visible privacy issues in the past, i.e. Is
not purely a theoretical concern.

4) Significantly furthers the privacy need.  I expect privacy advocates to
explain exactly how and to what extent a proposed restriction will further
the compelling privacy needs they have identified. Note that public
discussion of some specific privacy concerns or BAU purposes may be deemed
inappropriate, as more than good-intentioned people may be following this
list. Therefore we may need some process for discussion on a private list
or in F2F for specific items of particular sensitivity.

5) Justified minimization.  If there is a technical alternative to current
BAU technical approaches, the relative value of that approach must be
clarified by privacy advocates. The burden will be on privacy advocates to
show that an alternative technical approach has relative value in a
balance of privacy and commerce concerns (including estimation of
per-subscriber costs to switch to using the new technology/approach).





Without a clear justification in these terms, I would err on preservation
of BAU, within again within the blanket use restriction for cross-site
tracking.

Best Regards,
Bryan

On 2/1/12 6:45 PM, "Jonathan Mayer" <jmayer@stanford.edu> wrote:

>The working group has made great progress on the broad contours of the
>definition document, and the conversation is shifting to specific
>exceptions.  With that in mind, now seems an appropriate time to
>articulate my views on when and how exceptions should be granted.
>
>At a high level, we all agree that exceptions reflect a delicate balance
>between consumer privacy interests and commercial value.  There are, no
>doubt, substantial differences in opinion about where that balance should
>be struck.  I hope here to clarify my approach and help others understand
>why I find recent proposals for blanket exceptions to be non-starters.
>
>In my view, any exception must satisfy this rigorous six-part test.
>
>1) Specifically defined.  An exception must clearly delineate what data
>may be collected, retained, and used.  If a proposed exception is purely
>use-based, that needs to be extraordinarily explicit.
>
>2) No special treatment.  We should grant or deny an exception on the
>merits of how it balances privacy and commerce, not a specific business
>model.
>
>3) Compelling business need.  A bald assertion that without a specific
>exception Do Not Track will "break the Internet" is not nearly enough.  I
>expect industry stakeholders to explain, with specificity, what business
>purposes they need data for and why those business purposes are
>extraordinarily valuable.
>
>4) Significantly furthers the business need.  I expect industry
>participants to explain exactly how and to what extent a proposed
>exception will further the compelling business needs they have
>identified.  In some cases cases, such as security and fraud exceptions,
>this may call for technical briefing.
>
>5) Strict minimization.  If there is a privacy-preserving technology that
>has equivalent or nearly equivalent functionality, it must be used, and
>the exception must be no broader than that technology.  The burden is on
>industry to show that a privacy-preserving alternative involves tradeoffs
>that fundamentally undermine its business needs.  In the context of
>frequency capping, for example, I need to hear why - specifically -
>client-side storage approaches will not work.  In the context of market
>research, to take another example, I would need to hear why statistical
>inference from non-DNT users would be insufficient.
>
>6) Balancing.  There is a spectrum of possible exceptions for any
>business need.  At one end is a pure use-based exception that allows for
>all collection and retention.  At the other end is no exception at all.
>In between there are infinite combinations of collection, retention, and
>use limits, including exceptions scoped to privacy-preserving but
>inferior technologies.  In choosing among these alternatives, I am guided
>by the magnitude of commercial need and consumer privacy risk.  I am only
>willing to accept an exception where the commercial need substantially
>outweighs consumer privacy interests.
>
>I understand example exceptions may be helpful in understanding my
>thinking, so here are a few from the IETF Internet-Draft.
>
>>    3. Data that is, with high confidence, not linkable to a specific
>>        user or user agent.  This exception includes statistical
>>        aggregates of protocol logs, such as pageview statistics, so long
>>        as the aggregator takes reasonable steps to ensure the data does
>>        not reveal information about individual users, user agents,
>>        devices, or log records.  It also includes highly non-unique data
>>        stored in the user agent, such as cookies used for advertising
>>        frequency capping or sequencing.  This exception does not include
>>        anonymized data, which recent work has shown to be often re-
>>        identifiable (see [Narayanan09] and [Narayanan08]).
>>    4. Protocol logs, not aggregated across first parties, and subject
>>        to a two week retention period.
>>    5. Protocol logs used solely for advertising fraud detection, and
>>        subject to a one month retention period.
>>    6. Protocol logs used solely for security purposes such as intrusion
>>        detection and forensics, and subject to a six month retention
>>        period.
>>    7. Protocol logs used solely for financial fraud detection, and
>>        subject to a six month retention period.
>
>
>I would add, in closing, that in difficult cases I would err on the side
>of not granting an exception.  The exemption API is a policy safety
>valve: If we are too stringent, a third party can ask for a user's
>consent.  If we are too lax, users are left with no recourse.
>
>Best,
>Jonathan
>
>
Received on Thursday, 2 February 2012 04:07:40 UTC

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