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Re: [Action-106][Issue-32] Sharing of data between entities via cookie syncing / identity brokering

From: Aleecia M. McDonald <aleecia@aleecia.com>
Date: Wed, 15 Feb 2012 21:06:14 -0800
To: "public-tracking@w3.org (public-tracking@w3.org)" <public-tracking@w3.org>
Message-Id: <A52DA6F7-3E1B-4F58-814F-0F787D36B904@aleecia.com>
For the moment, I've included Vincent and Heather's text in the draft, plus added two notes to reflect comments from Rob and Shane --

Open issues:
This text does not cover Cross-Origin Resource Sharing (CORSE) and perhaps should.
Ad Exchanges use cookie synching for business purposes, including third-party auditing to verify ad impressions. However, this might be resolved with a service provider exemption.
If I failed to capture issues correctly, please let me know. Otherwise, we will leave this as pending review and resolve these after publishing the second public working draft.


On Feb 12, 2012, at 1:32 PM, Shane Wiley wrote:

> Vincent,
> Cookie syncing may be necessary for basic financial tracking across the Ad Exchange model - especially when 3rd party auditors are involved (each keeps a separate record of the ad impression and then leverages the Exchange cookie map to compare the number of impressions and where diverging results may be occurring, if any).  
> I agree that cookie syncing should be ceased for users with DNT:1 for the purposes of profiling and the use of profiles to modify a users experience.  I wanted to call out that a strict halting of the practices altogether will not be possible for much of the ad ecosystem for the serving of a very generic ad but this is done only in situations where a neutral technology vendor is being used and they have no independent right to use the information themselves (Service Provider exception).
> - Shane
> -----Original Message-----
> From: TOUBIANA, VINCENT (VINCENT) [mailto:Vincent.Toubiana@alcatel-lucent.com] 
> Sent: Wednesday, February 08, 2012 5:11 AM
> To: public-tracking@w3.org
> Cc: heatherwest@google.com
> Subject: [Action-106][Issue-32] Sharing of data between entities via cookie syncing / identity brokering
> The title might be misleading; it is not in fact about cookie-syncing between different browsers but different domains. Please find bellow the text that Heather and I drafted.
> Vincent
> Background:
> In a cookie syncing procedure a Demand-Side Platform (DSP) aim to match a cookieXYZ (corresponding to its domain) to the cookieABC set by the Supply Side Platform (SSP) for the same User-Agent U. Cookie syncing requires that the SSP adds a 1x1 pixel from the DSP domain. The SSP has to pass the string "cookieABC" corresponding to ids domain to the DSP through the URL of this 1x1 pixel. The DSP parses the "cookieABC" in the URL and associates it to the cookieXYZ for its domain. Once the cookies have been matches, the DSP will be able to re-target U on the SSP affiliated sites.
> The solution consists in not allowing cookie syncing when the SSP receives DNT:ON. If it did not, the SSP may start the cookie syncing process but the DSP must not synchronize the cookies if it received DNT:ON.
> *The reason is that if the SSP publishes ads on a limited number of websites, the DSP would know that the client visited at least one of these websites.*
> Pseudo-normative
> The operator of domain acting as a third party (SSP) on a website and receiving [DNT-ON]  MUST not load content from a second unaffiliated third party domain (DSP) to transfer a user ID to this third party.
> A third party receiving [DNT-ON] and a user ID through the URL loaded from an unaffiliated entity acting as a third party
> MUST NOT associate the ID of the cookie sent in the request to the user ID transmitted in the URL and
> MUST NOT collect or use other information related to that communication and not covered by the 3rd party exemption.

Received on Thursday, 16 February 2012 05:06:42 UTC

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