- From: Rob van Eijk <rob@blaeu.com>
- Date: Mon, 22 Jul 2013 14:27:07 +0200
- To: Ronan Heffernan <ronansan@gmail.com>
- Cc: "Mike O'Neill" <michael.oneill@baycloud.com>, Tracking Protection Working Group WG <public-tracking@w3.org>
? The ad contract is pretty specific: 7-times frequency cap on each creative and a 14-times frequency cap on the whole (6 creative) campaign, on a 6-month campaign That example sounds like a set of performance indicator for individual ads delivered to unique browsers, across sites and time. Rob Ronan Heffernan schreef op 2013-07-22 14:17: > This reporting is content-centric, being about the ads and campaigns, > not about the users, and the reporting would be solely statistical. > The report might be a set of counts as to how many users from each > country saw each ad once, how many saw it twice, etc. These are only > counts. No profiles are built about users. No information about users, > devices, history, etc. is included in and reports or shared with > advertisers. No user experiences are altered. > > --ronan > > On Monday, July 22, 2013, Rob van Eijk wrote: > > Ronan, > > You wrote: > > If the ad contract calls for a 7-times frequency cap on each creative > and a 14-times frequency cap on the whole (6 creative) campaign, on a > 6-month campaign, then the advertiser wants independent verification > that that clause was honored. That requires having counts per device, > not just "Hey, I think you're new." > > Sounds to me, that the ad contract is user centric, requiring having > counts per user impression. The justification for audience measurement > has been to allow for calibration. > The idea of having a unique identifier across sites with the > contractual clause you refer to, I fail to see the statistical analysis > that the text proposal is based upon. > > Exerpt from the audience meaurement text proposal: > > Audience measurement research creates statistical measures of the reach > in relation to the total online population, and frequency of exposure > of the content to the online audience, including paid components of web > pages. > > Rob > > Ronan Heffernan schreef op 2013-07-22 13:18: > > Mike, > There can't be a Last-Modified header except for objects that the > browser has cached. If we disable the mechanisms that prevent caching > (e.g. cache-buster parms), then proxies (corporate, ISP, etc.) will be > able to serve the pixels. You are also depending on the browsers to > still have that object in their cache, otherwise we will be counting > the user multiple times. This also has to work with mobile browsers > and embedded user agents, which may have tiny caches (or no cache), > and which often have unusual behavior around LastModified, ETag, > and/or caches surviving a power-cycle. > > This mechanism also only works if the pixel has the exact same > URL. That means that you can't point to the same pixel from multiple > ad networks or ad servers with different macro values (yes, this is > done today and will be required going forward), and you can't use both > HTTP and HTTPS. You also can't provide unique counts for a campaign > and a creative, since you will only be able to pass one of those IDs > or the other without getting multiple over-counts. > > One of the services that this kind of measurement provides is a > double-check that frequency-capping rules are working. This service > requires knowing how many times each device was exposed to an ad > and/or campaign. If the ad contract calls for a 7-times frequency cap > on each creative and a 14-times frequency cap on the whole (6 > creative) campaign, on a 6-month campaign, then the advertiser wants > independent verification that that clause was honored. That requires > having counts per device, not just "Hey, I think you're new." > > This is an interesting idea, and if industry can find ways to > work-around the problems, and can prove that this mechanism works > better, then you can expect that they will. Until that is able to > happen, there is no way to sign-off on such an unproven mechanism, > especially in light of the apparent problems. > > --ronan > > > > On Mon, Jul 22, 2013 at 4:20 AM, Mike O'Neill > <michael.oneill@baycloud.com> wrote: > > Ronan, > > > > You keep your own counts for ad impressions, they would not need to be > held in the browser, and it is up to the server how caching is > implemented. The ETag counts would be useful for frequency capping, > though you may not need to do that. > > > > Here is a demo of unique visitor detection (and low-entropy user-agent > specific counting) using cache headers I have knocked together. There > is no sharing/use of persistent unique identifiers, and no cookies. > > > > A new visit is communicated to the server by letting it know the time > of the previous visit so the server can update its aggregated counts. > There is no need to communicate a unique identifier so the individual > cannot be tracked. > > > > http://cloudclinic.com/HiImDory [1] [1] > > > > The duration between unique visits is set to 10 seconds to keep it > simple, but of course it could be any length of time. > > > > > > Mike > > > > > > FROM: Ronan Heffernan [mailto:ronansan@gmail.com] > SENT: 19 July 2013 22:02 > TO: Mike O'Neill; Tracking Protection Working Group WG > SUBJECT: Re: issue-25 > > > > Mike, > > Having the top-level page in the URL parameters means that the > incrementing ETag won't be incremented if the same ad is seen across > sites, since the browsers will cache a separate copy for each site > (since nearly all caching is URL-based)? BTW, we also issue a no-cache > header, and add a cache-busting parameter, to keep the browsers and > intermediate proxies from supplying the pixels out of cache. These are > standard practices. That means that the browsers should not be caching > the pixels or the current ETag value, so there will be no value for the > webservers to increment. > > If you are right that these techniques offer a superior way to function > in an environment that involves 3rd-party cookie blocking, then > industry will adopt them even with the audience measurement permitted > use exception. However, they do not seem to provide the functionality > that we need. > > --ronan > > > > > > On Fri, Jul 19, 2013 at 3:45 PM, Mike O'Neill > <michael.oneill@baycloud.com> wrote: > > Hi Ronan, > > > > If you read my first example I had a third-party element addressed via > a URI containing the first-party page in a query parameter, so making > the exchange top level page specific. It is not very complicated and it > works. > > > > In addition to being DNT compliant it also avoids the default > third-party cookie blocks which are becoming very common. > > > > Mike > > > > > > FROM: Ronan Heffernan [mailto:ronansan@gmail.com] > SENT: 19 July 2013 20:02 > > TO: Mike O'Neill > CC: Tracking Protection Working Group WG > SUBJECT: Re: issue-25 > > > > Mike, > > I call this improper because ETags already have a purpose and > semantics. If I understand you correctly, we would have to use the > exact same URL, so that the browser would use the ETag value that it > cached. This means that we could no longer use "cache-busting" > parameters, which means that intermediary proxies could serve the > content, which destroys audience measurement. I understand the desire > for really complicated, unproven, solutions, but none of the ones that > I have heard so far seem likely to work. We have a solution that > works, and is well proven. > > --ronan > > > > > On Fri, Jul 19, 2013 at 12:30 PM, Mike O'Neill > <michael.oneill@baycloud.com> wrote: > > Hi Ronan, > > > > No, not a unique identifier, which I agree would diminish privacy and > should be ruled out along with any other tracking identifier collection > when DNT is 1. What I meant was a count value (number of ad > impressions) which I assume would have limited entropy i.e. the max > value would be << the number of online individuals in scope. How many > ad impressions would you need to count? I agree relying on the cache > for 6 months would be a stretch, but do you need to do that? At some > point there may be some loss of functionality when DNT is 1 but the > setting is an important indication of user intent so needs to be > honoured. > > > > How an ETag is generated in not specified in the HTTP spec, so in what > way would this be “improper”? > > > > > > Mike > > . > > > > > > > > Links: > ------ > [1] http://cloudclinic.com/HiImDory [1] > > > Links: > ------ > [1] http://cloudclinic.com/HiImDory
Received on Monday, 22 July 2013 12:27:41 UTC