W3C home > Mailing lists > Public > public-tracking@w3.org > October 2011

Re: [ISSUE-81, ACTION-13] Response Header Format

From: Roy T. Fielding <fielding@gbiv.com>
Date: Sun, 30 Oct 2011 02:09:08 -0700
Cc: "public-tracking@w3.org Group WG" <public-tracking@w3.org>
Message-Id: <ED01DC27-E31E-4E0C-8D7B-06BD1FBD687B@gbiv.com>
To: Nicholas Doty <npdoty@w3.org>
On Oct 28, 2011, at 7:17 PM, Nicholas Doty wrote:
> On Oct 28, 2011, at 1:09 PM, Roy T. Fielding wrote:
>> The response is only necessary for the very small percentage of DNT enabled
>> browsers, which in turn is just a small percentage of overall browsers, that
>> also want to see verification of tracking.  In other words, the ultra-paranoid
>> mode or the regulators checking for deployment/compliance.  A user that just
>> wants to enable DNT will just send the DNT request header.
> 
> Do we think only "ultra-paranoid" users will have any interest in the response from the server? One of the goals we identified was to add visibility to the case of opting back in. This seems like a potentially very common situation, given the interest we've heard from advertisers and content providers in having a negotiation with users.

It isn't ultra-paranoid users -- it is a certain mode of browsing where the user
wants to be made aware of things like "this image came from a site that might be
tracking you".  It is one of those features that sounds okay at first, but ends
up being a visual nightmare for anyone other than a privacy researcher.

The case of opting-back-in is very different.  In that case, the website sees
that the user has DNT enabled and deliberately interrupts their normal behavior
in order to get consent for tracking (or some other alternative like login).
There is no need to change HTTP to accomplish that -- it can be just a redirect,
form, and cookie.  I suggested a new status code to make it visible to non-human
browsers, but I don't know if that is actually needed here.

> In fact, if the only effective signal that a user has opted-back-in will be the response header/well-known location, then I would suggest that all implementing user agents ought to check (through whichever mechanism) for every potential tracker. Otherwise it would be very easy for users to believe they've configured their browser to opt out and browse the Web while being regularly tracked.

If we want to see the browser config for user awareness, have the browser
display its own config.  There is no need for the server to do that.

We are talking about a preference expression. If any site wants to do bad
things, all they have to do is ignore the expression or always respond
that it is enabled.  Invisible network communication is neither a contract
nor a means of enforcement.

....Roy
Received on Sunday, 30 October 2011 09:09:35 UTC

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