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Re: The Rubber meets the Road - DNT compliance code

From: Peter Cranstone <peter.cranstone@gmail.com>
Date: Wed, 13 Jun 2012 09:28:26 -0600
To: <ifette@google.com>
CC: W3 Tracking <public-tracking@w3.org>
Message-ID: <CBFE0C82.31BE%peter.cranstone@gmail.com>

This is a case of win the battle on the forum but lose the war in the real
world. It doesn't matter if it's neither hard or complex. The point is that
it has to be done, tested and then updated and maintained. That requires
resources – not something that everyone can afford to do.

Secondly, lets flog the dead horse one more time on "who set the DNT flag".
If I have to write code that cannot guarantee 100% accuracy when it comes to
this privacy setting AND there are legal consequences of me getting said
code wrong (i.e. fines or pissed off customers) then I'm not going to do it.

We all know that per the spec that MSIE is not compliant because it sets the
flag by default. But what admin in his right mind is going to reject it? If
the server is DNT compliant then there is NO downside to MSIE setting the

We're back to stupid browser wars again and pissing off the customer. Not a
good thing.

Peter J. Cranstone

From:  "Ian Fette   (イアンフェッティ)" <ifette@google.com>
Reply-To:  <ifette@google.com>
Date:  Wednesday, June 13, 2012 9:22 AM
To:  Peter Cranstone <peter.cranstone@gmail.com>
Cc:  W3 Tracking <public-tracking@w3.org>
Subject:  Re: The Rubber meets the Road - DNT compliance code

> Many websites already do this -- "serve this JS to this user agent". It is
> neither complex nor hard.
> On Wed, Jun 13, 2012 at 7:44 AM, Peter Cranstone <peter.cranstone@gmail.com>
> wrote:
>> All,
>> There's a lot of questions around a non-compliant UA sending a DNT header.
>> There's still no definition on the forum or the spec on what constitutes a
>> non compliant UA, or even who is going to maintain a "blacklist" of those
>> non-compliant UA's. Finally there's no description of a message that should
>> be sent back to the consumer indicating that he's using a non-compliant UA.
>> So I'm posting a link today of what something might look like running on a
>> server. The reason this is in PHP is because there are lot of servers (in the
>> 10's of millions) that cannot suddenly start adding server side modules that
>> do the detection. So it will all have to be done via a script.
>> Think about this for a moment. In the real world server side admins are going
>> to have to add code to EVERY CGI script to do this. The performance hit is
>> going to be HUGE.
>> Here's the link: http://www.5o9mm.com/mod_dnt_test_1.php
>> We've blacklisted the following browsers:
>> HTTP_DNT_BLACKLISTED_USER_AGENT_1 = Mozilla/4.0 (compatible; MSIE 7.0;
>> Windows NT 6.1; Trident/5.0)
>> HTTP_DNT_BLACKLISTED_USER_AGENT_2 = Mozilla/5.0 (compatible; MSIE 9.0;
>> Windows NT 6.1; Trident/5.0)
>> HTTP_DNT_BLACKLISTED_USER_AGENT_3 = Mozilla/4.0 (compatible; MSIE 7.0;
>> Windows NT 6.0; Trident/5.0)
>> HTTP_DNT_BLACKLISTED_USER_AGENT_4 = Mozilla/5.0 (compatible; MSIE 9.0;
>> Windows NT 6.0; Trident/5.0)
>> HTTP_DNT_BLACKLISTED_USER_AGENT_5 = Mozilla/5.0 (Windows NT 6.0; rv:8.0.1)
>> Gecko/20100101 Firefox/8.0.1
>> So every time someone hits the Web site we have to run a check. The request
>> time for this check on our server is:
>> REQUEST_TIME = 1339597469
>> For that single page. Now multiply that by every page on your Web site that
>> is scripted. Ouch.
>> Now here's where it gets really interesting. Let's say that I'm on the
>> blacklist. What does the server do? By rights it should abort the entire
>> request and send a 400 invalid request response back to the user.
>> So what the heck does the user do now?
>> If this spec is going to be Trusted and used it has to work in the real world
>> which is NOT 100% technical. They turn it on (or have it turned on for them)
>> and they expect magic. They don't expect to be told that there browser is
>> non-compliant and they can either go get another one or get tracked.
>> Peter
>> ___________________________________
>> Peter J. Cranstone
>> 720.663.1752 <tel:720.663.1752>
Received on Wednesday, 13 June 2012 15:29:03 UTC

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