W3C home > Mailing lists > Public > public-tracking@w3.org > February 2013

Re: Concerns regarding "store"-style DNT exceptions Re: Batch closing of issues ISSUE-144

From: David Singer <singer@apple.com>
Date: Mon, 11 Feb 2013 11:40:33 -0500
Cc: "Matthias Schunter (Intel Corporation)" <mts-std@schunter.org>, Jonathan Mayer <jmayer@stanford.edu>, Shane Wiley <wileys@yahoo-inc.com>, "public-tracking@w3.org (public-tracking@w3.org)" <public-tracking@w3.org>
Message-id: <B59A4720-CA28-40FC-AC07-435658F5BDC1@apple.com>
To: Nicholas Doty <npdoty@w3.org>
Hi Nick

I think one of the major problems was being clear who was responsible for consent.  Previously, the site had to determine consent, and then the UA had to confirm it.

* That leaves it badly ambiguous; who exactly is responsible for the consent?  We don't want the sites and the UA each saying "well, we thought the other side was mostly responsible for explaining and getting consent".  The new model makes it very clear that the site gets consent, and the site has to explain.

* We all hate "are you sure?" prompts and modal interjections into our workflow.  If things work correctly, you've just visited a page at the publishing site, and they've explained what an exception is, why you might agree, and what the consequences are.  You click the page "yes, I agree" button and -- dang it! -- the UA puts up a "please confirm that you agree" dialog.  At best, it's annoying, and at worst, the terms and style used are sufficiently different that it's more confusing than helpful.


If we *do* start to see sites that call the exception API 'surreptitiously" I would expect to see the UAs do more to expose that.  They are *allowed* under the new model to (a) reject all calls (b) ask the user on all calls (c) expose all calls as a 'warning sign' somehow (d) expose the database for editing, either on demand, or after a change, or when they like (e) have a list of 'suspicious sites' such that when they call, much greater scrutiny is applied, and so on.



On Jan 31, 2013, at 5:03 , Nicholas Doty <npdoty@w3.org> wrote:

> I've raised concerns (in Amsterdam and on each subsequent call where we've discussed the proposed exception model), but this thread is a good opportunity to put them into writing. I will try to be clear and concise.
> 
> ## Incentives for different parties
> 
> As has rightly been pointed out, an entirely malicious third party actor need not use the exception mechanism to get a DNT: 0 signal sent. But given the first/third party model we're using, it will not generally be the party who calls storeTrackingException that receives the DNT: 0 signal. First party publishers who may receive higher revenue from their third-party advertising partners for visitors with DNT: 0 would be incentivized to call storeTrackingException to change the user's expressed preference to DNT: 0 even when the user might not actually want to do so. This could even be a malicious first party, but might commonly be a first party who misunderstands (copying and pasting code, as in the P3P CP example) or is incentivized to be unclear in obtaining consent.
> 
> This would be a bad experience for users, who would see their preferences reversed in potentially surprising ways, and lose faith in the DNT system. 
> 
> It would be bad for upstanding third parties who wish to rely on DNT: 0's affirmative meaning (or even rely on it meaning the absence of DNT: 1). If a third party wishes to ensure that the exception-granting consent was sufficiently clear and informed, that third party must investigate every first party it works with to make sure that storeTrackingException is only called under appropriate circumstances. We have already seen well-documented concerns raised about a particular browser vendor's set-up for sending DNT: 1 with suggestions from implementers that certain signals may be ignored. To allow any site at any time to change a user's expressed preference to DNT: 0 would create a much larger problem of vetting, as the number of first parties a third party works with is potentially very large in comparison to the number of major browser vendors. If a third party wants its users and regulators to be confident that users who turn on DNT: 1 will not be tracked without explicit consent, it may struggle to take advantage of DNT: 0 signals.
> 
> And it would be bad for upstanding first parties who may have competitors more willing to store tracking exceptions with less clear consent. If a competitor were able to increase its relative revenue by assuming consent via the Terms of Service and calling storeTrackingException on every page load, a first party who uses an interstitial or other more explicit consent process would be disadvantaged.
> 
> ## Enforcement via first parties
> 
> Can't we just ask the first parties who run this code inappropriately to stop? Given the number of sites on the Web, detecting and enforcing incorrect or less-than-ideal first-party uses of storeTrackingException() calls may not be feasible.
> 
> In the case of cookie-blocking policies in Internet Explorer based on P3P Compact Policy headers, many sites sent invalid or inaccurate headers without a clear understanding of the implications. These were certainly detectable cases (research papers were published based on crawling some portion of the Web), but lawsuits on these grounds have been, as far as I know, unsuccessful. Furthermore, without a detailed standard on consent necessary for these exceptions (which we in the WG have been understandably reluctant to get into), enforcement would be more difficult and less consistent. 
> 
> ## User interaction
> 
> Under some interpretations of the "store"-style proposal, it would be non-compliant for a user agent to ask a user to confirm before granting an exception and changing the user's expressed preference. Even implementations that allow for post-call revocation would create confusing mixed signals. To allow or require that the DNT signal be modified without the user's involvement inevitably casts doubt on the meaning of the signal.
> 
> By potentially reducing user control and increasing second-guessing around DNT: 0 signals, I would be concerned about moving forward with a "store"-style model for user-agent managed user-granted exceptions.
> 
> ## Alternatives
> 
> Previous drafts of this API have required that the user agent (of which there are many fewer; which might operate under difference incentives; which might be configured by the user) would determine with the user whether an exception should be granted or stored. Involving the user and the user's agent makes the meaning of DNT: 0 more consistent.
> 
> It may be that if the API were constructed in a way that it was possible for a user agent to confirm exception requests with the user that these concerns would be less strong. We have discussed this on past calls, but it's not clear that the store approach can accommodate this.
> 
> Thanks,
> Nick
> 



David Singer
Multimedia and Software Standards, Apple Inc.
Received on Monday, 11 February 2013 16:41:07 UTC

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