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: Sean Harvey <sharvey@google.com>
Date: Sun, 5 Feb 2012 22:57:01 +0100
Message-ID: <CAFy-vucoELPtr+GpY5mvjSAaNykfTjinASqONpKFtGX_E4bstQ@mail.gmail.com>
To: Jonathan Mayer <jmayer@stanford.edu>
Cc: Matthias Schunter <mts@zurich.ibm.com>, Jeffrey Chester <jeff@democraticmedia.org>, "public-tracking@w3.org (public-tracking@w3.org)" <public-tracking@w3.org>
I want to comment on Jonathan's original email on this chain, in the
context of his later response below. Jonathan's thoughts are in general
well thought out. To my mind the main stumbling block is his elaboration of
#5, which was titled "Minimization" but focused on the use of "privacy
enhancing alternatives".

In light of our both our meeting in Brussels and Jonathan's later post to
this email chain, it's clear that Jonathan is speaking of his own personal
version of client-side frequency capping, and so I feel forced to address
this issue, though it seems tangential to our goals.

To put it simply, client-side frequency capping does not work at scale.

There were two separate initiatives at DoubleClick prior to its acquisition
by Google that attempted to move functionality like frequency capping onto
the client-side. Both looked nice when you did a little demo of them. But
none of the worked at scale across a system -- like the ones that will be
most directly impacted by these discussions -- that transact tens of
billions of events per day. Discussing in further detail would be
inappropriate in the context of this list because of proprietary technology
concerns, but suffice it to say that client-side frequency capping and
other such ad serving capabilities crap out at scale.

This is not to say that Jonathan is not extremely intelligent or that his
idea isn't a good one, but he does not have the hard experience of many
years spent building & maintaining massively scaleable software systems
that must never go down at risk of the financial viability of tens of
thousands of businesses across the web. And we do have many other women &
men who are every bit as intelligent running our ad serving & other systems.

I am also unconvinced that retaining such data on the client side is a data
privacy & security improvement for physical security reasons, because
clients (e.g. browsers on laptops) are far more easily stolen than servers
on data farms. While it's true that there would be no human readable values
on the client side that an individual could leverage, the same remains true
of the frequency cap ticks that are currently stored on the server-side.

I think it is entirely valid & useful for us to discuss openly the merits
of a frequency cap exception, but do not think it is legitimate for us to
make potentially disastrous technical implementation requirements in the
context of this W3C compliance process.

sean









On Sat, Feb 4, 2012 at 1:17 AM, Jonathan Mayer <jmayer@stanford.edu> wrote:

> Here are a few exceptions that I believe could clear the hurdle.
>
> -Content serving
> -Contextual personalization
> -Outsourcing
> -Protocol logs for debugging
> -Unidentifiable data (including aggregated data and client-side frequency
> capping)
> -View fraud prevention through a stepped response
>
> On Feb 2, 2012, at 7:06 AM, Matthias Schunter wrote:
>
> > Hi Jonathan/Jeff,
> >
> > what exeptions do you see at this point that are likely to satisfy this
> > catalogue?
> > what are viable candidates where only  more data/input/answers is needed?
> >
> > Regards,
> > matthias
> >
> >
> >
> >
> > |------------>
> > | From:      |
> > |------------>
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> >  |Jeffrey Chester <jeff@democraticmedia.org>
>                                                                     |
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> > |------------>
> > | To:        |
> > |------------>
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> >  |Jonathan Mayer <jmayer@stanford.edu>,
>                                                                    |
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> > |------------>
> > | Cc:        |
> > |------------>
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> >  |"public-tracking@w3.org (public-tracking@w3.org)" <
> public-tracking@w3.org>
>             |
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> > |------------>
> > | Date:      |
> > |------------>
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> >  |02/02/2012 03:34 PM
>                                                                    |
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> > |------------>
> > | Subject:   |
> > |------------>
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> >  |Re: Deciding Exceptions (ISSUE-23, ISSUE-24, ISSUE-25, ISSUE-31,
>  ISSUE-34, ISSUE-49)                                                    |
> >>
> -----------------------------------------------------------------------------------------------------------------------------------------|
> >
> >
> >
> >
> >
> > I agree with Jonathan's thoughtful discussion of the exemption issue.  I
> > recognize this is a delicate matter, and it will require continued
> dialogue
> > to properly balance the goal's of DNT with traditional digital marketing
> > (and advertising generally) business practices.  I believe that if we
> > follow Jonathan's outline, we can achieve our collective goals.
> >
> > Jeff
> >
> > On Feb 1, 2012, at 9:45 PM, Jonathan Mayer 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
> >
> >
> >
> >
> >
>
>
>


-- 
Sean Harvey
Business Product Manager
Google, Inc.
212-381-5330
sharvey@google.com
Received on Sunday, 5 February 2012 21:57:30 UTC

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