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

Re: Frequency Capping

From: Grimmelmann, James <James.Grimmelmann@nyls.edu>
Date: Thu, 12 Jul 2012 01:35:50 +0000
To: Chris Mejia <chris.mejia@iab.net>
CC: David Wainberg - NAI <david@networkadvertising.org>, W3C DNT Working Group Mailing List <public-tracking@w3.org>, Mike Zaneis <mike@iab.net>, Brendan Riordan-Butterworth <Brendan@iab.net>
Message-ID: <6E590B4E-61A5-4874-B68B-9A52E95DB83D@nyls.edu>
I meant the phrase "attenuated threat model" to be reassuring, not accusatory.  Let me say a bit more, and hopefully it will be genuinely reassuring.

What I was trying to emphasize is that frequency counting as described in Brian O'Kelley's comment REDUCES privacy concerns compared with tracking browsing history.  Someone who was going to do something privacy violating -- e.g. leak to the Washington Post a list of some of the websites I visit -- will have a much harder time starting from frequency counts than from a browsing history.  The "threat model" of how frequency counts could be used against me is "attenuated" compared with the threats from browsing history.  There is less to worry about.

At the same time, frequency counts do still store some information that is unique to the user and that is related to the user's browsing history.  If a given ad only runs on sites A, B, and C, and the user has seen that ad, then the user has visited one or more of sites A, B, or C.  Someone with access to the provider's information about campaigns could use that, plus a given user's frequency counts, to make educated guesses about the user's browsing history.  The guesses might be better, or might be worse, depending on how narrowly or broadly the ads seen by the user were displayed.  But they will be better than random because the guesser has access to some information about the user's activity.  How much better depends a lot on the details.

Thus, the possible privacy implications are "attenuated" compared to a full-tracking baseline, but they don't disappear entirely.  Some users may care more and some may care less about it.

James

--------------------------------------------------
James Grimmelmann              Professor of Law
New York Law School                 (212) 431-2864
185 West Broadway       james.grimmelmann@nyls.edu<mailto:james.grimmelmann@nyls.edu>
New York, NY 10013    http://james.grimmelmann.net

On Jul 11, 2012, at 7:58 PM, Chris Mejia wrote:

James, can you please point to the actual research (or proof) you or others have conducted that supports the notion you propose in the rather strong accusatory statement below, that the practice of f-capping poses an "attenuated threat model"?

"But in some cases, information about the browsing history can be reconstructed with some better-than-random probability by observing the counts and combining that information with the provider's records of campaigns. That is, to be sure, a pretty attenuated threat model."

I haven't seen that research myself, which is curious, since I live and breath this stuff.  But there is a lot of information out there and I'm certainly nowhere near an expert on all of it, so if it exists, let's all review the real data.  Thanks in advance for sharing data that supports your stated hypothesis.

Chris Mejia | Digital Supply Chain Solutions | Ad Technology Group | Interactive Advertising Bureau - IAB



On 7/11/12 7:48 PM, "Grimmelmann, James" <James.Grimmelmann@nyls.edu<mailto:James.Grimmelmann@nyls.edu>> wrote:

Pure frequency-counting has the advantage of not directly storing browsing history.  But in some cases, information about the browsing history can be reconstructed with some better-than-random probability by observing the counts and combining that information with the provider's records of campaigns.  That is, to be sure, a pretty attenuated threat model.  But it still involves storing some detailed information.

I expect that some users who object to being "tracked" will consider this to be completely fine.  Some may not.  As far as possible, I don't want to be in the position of telling any of these users that they're right or wrong about their privacy.  I favor giving all of them good information about what storage and tracking is actually happening, and giving those who object to particular practices the means to request exclusion from them.

James

--------------------------------------------------
James Grimmelmann             Professor of Law
New York Law School                 (212) 431-2864
185 West Broadway       james.grimmelmann@nyls.edu<mailto:james.grimmelmann@nyls.edu>
New York, NY 10013    http://james.grimmelmann.net<http://james.grimmelmann.net/>

On Jul 11, 2012, at 4:58 PM, David Wainberg wrote:

Hi James,
To me, the implementation of frequency capping that Brian describes is quite privacy friendly. It records only the number of times a particular UA was delivered a particular ad, or when was the last time that UA saw an ad from a particular advertiser. Is that tracking? What is the privacy impact of it? I'm not asking rhetorically. I'm very interested in hearing why what Brian described is not already privacy-friendly enough. I honestly don't get why this model of frequency capping would be included in DNT.
Cheers,
David
On 7/11/12 4:07 PM, Grimmelmann, James wrote:
Chris, I think you are missing the point of my comment.
Like Jonathan, I would like to see a detailed conversation on whether advertisers' and publishers' interests behind frequency capping could be addressed in ways that are not identical to frequency capping as it is practiced today.  By saying that frequency capping is required by advertiser contracts, you were cutting off that conversation before it could even get started.  Jonathan was brainstorming for ways to limit user exposure to the same ad that require less tracking than pure frequency capping.  I'd like to know what "good enough" frequency capping would look like and whether it would actually be good enough.  Please help in that effort, and don't just say, "It can't be done."
James
On Jul 11, 2012, at 3:27 PM, Chris Mejia wrote:
James,
Since I didn't go into the obvious details before, I will dive a little
deeper here, as I realize now that many on this forum are not intimately
experienced with the actual business of digital advertising.  I hope you
will appreciate that the digital advertising industry carefully balances
business concerns with user concerns (thus the "win-win" model we have
proven works--consumers and thus consumer protection are key to our
success).
With regards to f-capping on the side of user concerns, as I previously
stated, advertisers AND publishers do not want to annoy users with
repeated delivery of the same ad creative.  Nor is the repeated delivery
of the same ad creative to the same user a good business practice for
advertisers and publishers.  There is always a monetary cost associated
with the delivery of an ad impression (such as the cost of ad serving and
the overhead of campaign management).  So the assertion that we just spray
the same ads indiscriminately onto those who have turned on DNT:1 will not
only be found utterly annoying to those users (at the additional cost of
negative consumer brand association for those advertisers), it also costs
real money.  Remember, every single impression served costs actual
money--and aggregated, the cost of serving billions of impressions daily
is not trivial (take away here = nothing that happens on the Internet is
actually "free" of costs).  When a publisher's cost goes up, those costs
are passed to the advertiser (and ultimately to the consumer). So when the
publisher serves more ads (in this case, as a result of NOT f-capping a
campaign), the publisher charges the advertiser for those additional
served impressions.  The idea that this increased cost be paid for by
publishers and advertisers, on behalf of those users who are opting out of
the publisher:consumer value exchange (when these consumers effectively
'devalue' themselves in the value exchange by turning on DNT:1), goes
against the laws of market economics.  If you think advertisers are not
going to require f-capping, think again.  Advertisers have plenty of
reasonable business reasons to require f-capping in their contracts:  i.e.
a) not annoy consumers with overdelivery when such annoyance leads to
negative advertiser brand association, and b) not needlessly waste ad
impressions and money on serving ads over and over again to users who have
opted out of the value exchange in the first place.  Again, f-capping
represents a win-win practice for industry AND users, even those users who
have opted out with DNT:1.
Since we are on the topic of publishing costs and the value exchange that
pays for these costs so that content may be delivered to users, I'm very
concerned about the end game of an irresponsible DNT specification (just
as a reminder, I am FOR a responsible, balanced and well thought out DNT
spec).  In the world of ubiquitous DNT:1 signals that many advocates on
this forum support, what do you suppose will be the necessary
business-motivated recourse for most for-profit publishers?  My educated
guess is the rapid proliferation of payment gateways, with subscription
services paying for content when advertising alone no longer supports the
publishing of "free" content.
In this case, is the W3C inadvertently, but consequently promoting the
idea of a new digital divide?  A divide where those with wealth and credit
cards afford access to professionally developed content, while those
without sufficient wealth will be blocked from accessing the same?  If you
don't think this is a realistic outcome, please explain precisely how
professionally developed content will be paid for without sufficient
advertising revenue.  Remember, real costs must be paid for with real
dollars.
Is the answer that the reduction in revenue that a ubiquitous DNT:1 will
undoubtedly bring, mean that publishers should scale back innovation, cut
jobs, slow investment in the future?  Should all consumers pay this price?
In a free market economy, I'm going to bet that innovation will actually
not slow; BUT it will be shifted to focus on only those who can afford to
pay for it.  Will government pay for the the (less financially fortunate)
others?  Will non-profit consumer advocates pay for 'the others' to access
this premium content?  Today, the vast majority of that online innovation
and premium content is paid for by the publisher:consumer value exchange
(advertising pays for innovation, content and access to that content).
And how about the free press?  Who will pay for the free press?  Over the
last 10-years we have experienced a severe reduction in subsidized
regional newspaper content as a result of underperforming advertising
revenues (economy/recession related?) for local news organizations.
Consequently, to reduce costs, most regional newspapers who have survived
(or are just barely hanging on in some cases) are restructuring their
service to less costly Web-only publishing models.  But even Web
publishing costs money, and ad revenues per impression are far less online
than they were in print.  So when these newspapers (the free, advertising
supported, press) cannot afford to self-sustain online, who will pay to
replace their professional news reporting?  Are we all comfortable moving
to a government funded press model?  If this sounds ridiculous, have a
look at the trend:
http://online.wsj.com/public/resources/documents/NEWSPAPERS0903.html.  In
conclusion, I'll step off my soapbox as soon as those who questions such
reasonable win-win practices as f-capping step off theirs, and we all
start working together on reasonable win-win solutions.
Chris Mejia | Digital Supply Chain Solutions | Ad Technology Group |
Interactive Advertising Bureau - IAB
On 7/11/12 1:31 PM, "Grimmelmann, James" <James.Grimmelmann@nyls.edu<mailto:James.Grimmelmann@nyls.edu>>
wrote:
Advertisers require frequency capping in insertion orders because ad
deliverers are capable of providing it.  If an ad deliverer were to say
that it could not promise pure frequency capping for users who have
requested DNT, but only some best-efforts version such as the one
Jonathan outlines, the deliverer simply wouldn't let advertisers write
that term into their contracts with it.  Of course, this might come at
some cost to the deliverer, and that tradeoff is a fair subject for
discussion.  But let's not mistake the "requirements" of current
advertising contracts for the requirements of the future advertising
contracts that will be written in view of the DNT standard and various
parties' implementations of it.
I would add that since the primary motivation of frequency capping is to
reduce user annoyance, users ought to be given the chance to choose for
themselves whether to suffer that annoyance or the annoyance of being
tracked for frequency capping purposes.
James
--------------------------------------------------
James Grimmelmann              Professor of Law
New York Law School                 (212) 431-2864
185 West Broadway
james.grimmelmann@nyls.edu<mailto:james.grimmelmann@nyls.edu><mailto:james.grimmelmann@nyls.edu>
New York, NY 10013    http://james.grimmelmann.net<http://james.grimmelmann.net/>
On Jul 11, 2012, at 12:59 PM, Chris Mejia wrote:
Jonathan,
Frequency capping (f-capping) is usually a contractual obligation for the
party responsible for delivering the ad (an ad-netork, a publisher, and
exchange, etc.) and is almost always required by the advertiser in
insertion orders (the insertion order or "IO" is the contract between the
parties).  It looks like your assumption below is that f-capping is
(only) a 'tactic' to increase ROI for performance campaigns.  While this
is sometimes true (yet mostly not), it's actually rarely the real
motivation of doing f-capping.  The requirement for f-capping the
delivery of a campaign to users is generally contractually obligated by
the advertiser, for several good reasons, but most importantly for not
annoying the user with multiple servings of the same ad creative, over
and over again in one time frame (i.e. in a 24-hour time period).
As f-capping is generally contractually obligated, it's not up to the
deliverer of the ad to CHOOSE which campaigns to f-cap‹ it's a
REQUIREMENT to f-cap all campaigns where contractually obligated to do
so.  F-capping has happened in television advertising for many years‹
imagine how annoying it is when the same tv ad spot plays over and over
again (in fact this happens, and I'm sure we all find it annoying).
To sum up, while f-capping can sometimes increase ROI for advertisers
(it's not necessarily always true), it is most often contractually
obligated (per the Insertion Order).  The primary motivation for
f-capping is to not annoy the user with repeated serving of the same ad
creative during a time period.  In my experience, the vast majority of
f-capping is  set at 1:24 or 2:24, etc. (restricting the showing of a
particular ad creative, 1 time in 24-hours, or 2-times in 24-hours).
I hope this helps clarify the motivation for f-capping and leads to
mutual appreciation for the need.
Kind Regards,
Chris
Chris Mejia | Digital Supply Chain Solutions | Ad Technology Group |
Interactive Advertising Bureau - IAB
From: Jonathan Mayer <jmayer@stanford.edu<mailto:jmayer@stanford.edu><mailto:jmayer@stanford.edu><mailto:jmayer@stanford.edu%3E>>
Date: Tue, 10 Jul 2012 14:26:12 -0700
To: David Wainberg - NAI
<david@networkadvertising.org<mailto:david@networkadvertising.org><mailto:david@networkadvertising.org><mailto:david@networkadvertising.org%3E>>
Cc: W3C DNT Working Group Mailing List
<public-tracking@w3.org<mailto:public-tracking@w3.org><mailto:public-tracking@w3.org><mailto:public-tracking@w3.org%3E>>
Subject: Re: Frequency Capping
Resent-From: W3C DNT Working Group Mailing List
<public-tracking@w3.org<mailto:public-tracking@w3.org><mailto:public-tracking@w3.org><mailto:public-tracking@w3.org%3E>>
Resent-Date: Tue, 10 Jul 2012 21:26:46 +0000
I'd sure like to hear more from advertising industry participants about
how frequency capping integrates into advertisement selection.  The
AppNexus approach, if I read correctly, goes roughly as follows:
1) Begin with the set of all campaigns.
2) Filter by targeting criteria.
3) Filter by frequency capping.
4) Assign an expected revenue to each campaign.
5) Select the campaign with greatest expected revenue.
The approach includes testing the frequency cap of every campaign that
matches targeting criteria.  What about, instead, only testing the cap
for a subset of those campaigns:
1) Begin with the set of all campaigns.
2) Filter by targeting criteria.
3) Assign an expected revenue to each campaign.
4) Select the n campaigns with greatest expected revenue.
5) Filter by frequency capping.
6) Select the campaign with greatest expected revenue.
Some relevant empirical questions include: How often are the highest
revenue campaigns frequency capped?  How well can an ad company predict
which high-revenue campaigns will and won't be frequency capped?
Jonathan
On Monday, July 9, 2012 at 11:34 AM, David Wainberg wrote:
Hi All,
In case you haven't seen it already, I recommend Prof. Felten's excellent
blog on "Privacy by Design: Frequency Capping." Please also read Brian
O'Kelley's post in the comment section explaining what he sees as the
technical hurdles for these alternative frequency capping methods. (I may
be wrong, but I think Brian is a former student of Prof. Felten.) This
kind of detailed technical discussion of these proposals seems very
helpful. First, it helps us set reasonable expectations on all sides.
Second, and more interesting to me, is that maybe we can have more
discussion and collaboration on bringing these sorts of things to
production.
http://techatftc.wordpress.com/2012/07/03/privacy-by-design-frequency-capp
ing/
-David
Received on Thursday, 12 July 2012 01:37:05 UTC

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