[66] [DFN[DNT]] ([DFN[Do Not Track]]) は、
[[利用者]]の情報などの[[追跡]]を拒否する意思を[[HTTPサーバー]]に対して表明するための
[[HTTPヘッダー]]です。

[67] [[Webサイト]]は、適切な[[広告]]の表示や[[利用者]]の行動の分析などの目的で、
[[HTTPサーバー]]側で得られる情報を使って、あるいは [[JavaScript]]
により[[Webサーバー]]上で得られる情報を[[HTTPサーバー]]に送信することで、
[[利用者]]の属性に関する情報や[[利用者]]の行動履歴などを収集し、
蓄積し、時には第三者に提供することがあります。
しかし、こうした行為は[[利用者]]の[[プライバシー]]を侵害するものだと考える人もいます。

[68] 本[[ヘッダー]]は、そうした[[追跡]]行為を拒絶する意思を表明するものです。
本[[ヘッダー]]自体にはそうした行為を技術的に停止させる機能はありませんし、
[[Web]] の仕組み上、技術的に完全に拒絶することは不可能です。
[[Webサイト]]運営者が[[利用者]]の意思を尊重することで、本機能は成立します。

* 仕様書

[REFS[
- [49] [CITE@en[Tracking Preference Expression (DNT)]] ([TIME[2016-03-08 07:46:07 +09:00]]) <https://www.w3.org/2011/tracking-protection/drafts/tracking-dnt.html>
]REFS]

* 文脈

[69] [[HTTP要求]]に指定できます。

* セキュリティー

[70] 前述の通り、本機能によって技術的に[[追跡]]を抑制できるわけではありません。
本機能を尊重する意思のない[[著者]]や悪意を持った[[著者]]は、
本機能による表明の有無に関わらず情報を収集できます。

[71] むしろ本機能自体が [[fingerprinting vector]] でもあります。

* 処理

[88] 指定があった場合にどう扱うかは、完全に[[Webアプリケーション]]側の裁量となります。

[89] [TIME[2017年][year:2017]]には、[[Twitter]] が業界の足並みが揃わなかったとして対応を廃止しました
[SRC[>>63]]。 [[DNT]] に対応している他の (わずかな) [[Webアプリケーション]]事業者もこれに追随するか気になります。

[90] [[広告]]業界各社はそれぞれの [[Webサイト]] (や業界団体の [[Webサイト]])
で個別に設定の手段を提供するのが一般的になっています。
個別に設定しなければならないのなら、 [[Webブラウザー]]で一度設定すれば良い [[DNT]]
より[[利用者]]に不便、と思うかもしれませんが、それは [[DNT]]
をすべての業者が遵守していればの話。実際にはそれを確認して回らなければならない
(そして多分確認のしようがない) ので、[[利用者]]の手間は変わりません。
それより、追跡や広告を気にする[[利用者]]は、むしろより強力で手軽な[[広告ブロック機能]]を使うことでしょう。

* HTTP ヘッダー

[117] [CODE[DNT:]] の他に [CODE[Tk:]] が提案されていました。

* API

[FIG(middle list)[ [116] [[DNT]] [[DOM API]]
- [CODE[doNotTrack]]
- [CODE[storeTrackingException]]
- [CODE[removeTrackingException]]
- [CODE[trackingExceptionExists]]
]FIG]

* 歴史

[45] [CITE@en[Report -- W3C Workshop on Web Tracking and User Privacy]]
( ([TIME[2011-05-26 05:23:26 +09:00]] 版))
<http://www.w3.org/2011/track-privacy/report.html>

[44] [CITE@en[Web Tracking Protection]]
( ([TIME[2011-02-24 23:18:00 +09:00]] 版))
<http://www.w3.org/Submission/web-tracking-protection/>

[1] [CITE@en[Web Tracking Protection]]
( ([TIME[2011-02-24 23:18:00 +09:00]] 版))
<http://www.w3.org/Submission/2011/SUBM-web-tracking-protection-20110224/>

[2] [CITE[Bug 628197 – Implement do-not-track HTTP header]]
( ([TIME[2011-03-07 22:14:16 +09:00]] 版))
<https://bugzilla.mozilla.org/show_bug.cgi?id=628197>

[3] [CITE[Bug 628198 – Implement UI for do-not-track HTTP header]]
( ([TIME[2011-03-07 22:14:18 +09:00]] 版))
<https://bugzilla.mozilla.org/show_bug.cgi?id=628198>

[4] [CITE@en[Privacy/Jan2011 DoNotTrack FAQ - MozillaWiki]]
( ([TIME[2011-01-25 06:56:54 +09:00]] 版))
<https://wiki.mozilla.org/Privacy/Jan2011_DoNotTrack_FAQ>

[5] [CITE@en[Do Not Track at W3C - W3C Blog]]
( ([TIME[2011-03-04 09:51:07 +09:00]] 版))
<http://www.w3.org/QA/2011/02/do_not_track_at_w3c.html>

[6] [CITE@en[draft-mayer-do-not-track-00 - Do Not Track: A Universal Third-Party Web Tracking Opt Out]]
( ([TIME[2011-06-19 19:42:51 +09:00]] 版))
<http://tools.ietf.org/html/draft-mayer-do-not-track-00>

[7] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2011-11-14 21:47:00 +09:00]] 版))
<http://www.w3.org/TR/2011/WD-tracking-dnt-20111114/>

[8] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2011-11-14 21:17:18 +09:00]] 版))
<http://www.w3.org/TR/2011/WD-tracking-compliance-20111114/>

[9] [CITE@en-US[W3C Announces First Draft of Standard for Online Privacy]]
( ([TIME[2011-11-15 00:01:07 +09:00]] 版))
<http://www.w3.org/2011/11/dnt-pr.html.en>

[10] [CITE[Testimonials for: W3C Announces First Draft of Standard for Online Privacy]]
( ([TIME[2011-11-14 13:34:41 +09:00]] 版))
<http://www.w3.org/2011/11/dnt-testimonials>

[11] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2012-03-13 23:28:30 +09:00]] 版))
<http://www.w3.org/TR/2012/WD-tracking-dnt-20120313/>

[12] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2012-03-13 23:28:30 +09:00]] 版))
<http://www.w3.org/TR/2012/WD-tracking-compliance-20120313/>

[13] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2012-05-16 23:18:25 +09:00]] 版))
<http://www.w3.org/2011/tracking-protection/drafts/tracking-dnt.html>

[14] [CITE@en-US[Do Not Track Gains More Support around the Web | The Mozilla Blog]]
( ([TIME[2012-05-18 08:01:45 +09:00]] 版))
<http://blog.mozilla.org/blog/2012/05/17/do-not-track-gains-more-support-around-the-web/>

[15] [CITE@ja[「トラッキングお断り」の動きが広まる―TwitterもMozillaのDo Not Trackをサポート]]
( ([TIME[2012-05-18 07:56:13 +09:00]] 版))
<http://jp.techcrunch.com/archives/20120517twitter-now-honors-mozillas-do-not-track-feature/>

[16] [CITE[Mozilla: Do Not Track]]
( ([TIME[2012-05-18 08:02:24 +09:00]] 版))
<http://dnt.mozilla.org/>

[17] [CITE@en[draft-mayer-do-not-track-00 - Do Not Track: A Universal Third-Party Web Tracking Opt Out]]
( ([TIME[2012-04-08 07:15:53 +09:00]] 版))
<http://tools.ietf.org/html/draft-mayer-do-not-track-00>

[18] [CITE@ja[Twitter、主要ブラウザでの「Do Not Track」サポートを発表 - ITmedia ニュース]]
([TIME[2012-05-18 13:32:03 +09:00]] 版)
<http://www.itmedia.co.jp/news/articles/1205/18/news031.html>

[19] [CITE@ja[マイクロソフトが次期ブラウザのDo Not Track機能をデフォルトでオンに、米ネット広告業界団体が懸念を表明 (1/1):MarkeZine(マーケジン)]]
([TIME[2012-06-01 14:04:51 +09:00]] 版)
<http://markezine.jp/article/detail/15774>

[20] [CITE@ja-JP[Windows 8 Release Preview の提供開始を発表]]
([TIME[2012-06-01 14:09:17 +09:00]] 版)
<http://www.microsoft.com/japan/presspass/detail.aspx?newsid=4164>

[21] [CITE[IRC logs: freenode / #whatwg / 20120601]]
( ([TIME[2012-06-22 21:46:04 +09:00]] 版))
<http://krijnhoetmer.nl/irc-logs/whatwg/20120601#l-1044>

[22] [CITE@en-US[Tracking Preference Expression Patent Advisory Group Charter (DNT PAG)]]
( ([[Rigo Wenning]] 著, [TIME[2012-08-02 02:36:46 +09:00]] 版))
<http://www.w3.org/2012/06/dnt-pag-charter.html>

[23] [CITE[Apache does not tolerate deliberate abuse of open standards · a381ff3 · apache/httpd]]
( ([TIME[2012-09-10 11:16:06 +09:00]] 版))
<https://github.com/apache/httpd/commit/a381ff35fa4d50a5f7b9f64300dfd98859dee8d0>

[24] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2012-10-02 05:47:20 +09:00]] 版))
<http://www.w3.org/TR/2012/WD-tracking-compliance-20121002/>

[25] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2012-10-02 05:49:43 +09:00]] 版))
<http://www.w3.org/TR/2012/WD-tracking-dnt-20121002/>

[26] [CITE[Do Not Track and Beyond - W3C Workshop]]
( ([TIME[2013-03-05 00:23:49 +09:00]] 版))
<http://www.w3.org/2012/dnt-ws/report>

[27] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2013-04-29 16:49:22 +09:00]] 版))
<http://www.w3.org/TR/2013/WD-tracking-dnt-20130430/>

[28] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2013-04-29 16:49:22 +09:00]] 版))
<http://www.w3.org/TR/2013/WD-tracking-compliance-20130430/>

[29] [CITE[Experimenting with new ways to tailor ads | Twitter Blog]]
( ([TIME[2013-07-16 07:35:19 +09:00]] 版))
<https://blog.twitter.com/2013/experimenting-with-new-ways-to-tailor-ads>

[30] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2013-09-13 06:46:28 +09:00]] 版))
<http://www.w3.org/TR/2013/WD-tracking-dnt-20130912/>

[31] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2013-09-13 06:39:48 +09:00]] 版))
<http://www.w3.org/TR/2013/WD-tracking-compliance-20130912/>

[32] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2014-01-27 10:35:46 +09:00]] 版))
<http://www.w3.org/TR/2014/WD-tracking-compliance-20140128/>

[33] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2014-01-27 10:52:26 +09:00]] 版))
<http://www.w3.org/TR/2014/WD-tracking-dnt-20140128/>

[34] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2014-04-24 09:03:35 +09:00]] 版))
<http://www.w3.org/TR/2014/WD-tracking-dnt-20140424/>

[35] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2014-05-07 16:12:37 +09:00]] 版))
<http://www.w3.org/TR/2014/WD-tracking-compliance-20140508/>

[36] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2014-08-06 15:31:48 +09:00]] 版))
<http://www.w3.org/TR/2014/WD-tracking-compliance-20140807/>

[37] [CITE@en[Web Tracking Protection Submission Request to W3C]]
( ([TIME[2011-02-28 20:01:09 +09:00]] 版))
<http://www.w3.org/Submission/2011/01/>

[38] [CITE@en[draft-cooper-web-tracking-opt-outs-00 - Overview of Universal Opt-Out Mechanisms for Web Tracking]]
( ([TIME[2014-10-17 02:27:51 +09:00]] 版))
<https://tools.ietf.org/html/draft-cooper-web-tracking-opt-outs-00>

[39] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2014-11-24 13:45:27 +09:00]] 版))
<http://www.w3.org/TR/2014/WD-tracking-compliance-20141125/>

[40] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2015-03-30 17:10:07 +09:00]] 版))
<http://www.w3.org/TR/2015/WD-tracking-compliance-20150331/>

[41] [CITE@en[Tracking Preference Expression Patent Advisory Group Report]]
( ([TIME[2015-05-21 09:24:04 +09:00]] 版))
<http://www.w3.org/2012/dnt-pag/pagreport.html>

[42] [CITE@en[Tracking Compliance and Scope]]
( ([TIME[2015-07-13 15:45:38 +09:00]] 版))
<http://www.w3.org/TR/2015/WD-tracking-compliance-20150714/>

[43] [CITE@en[Tracking Preference Expression (DNT)]]
( ([TIME[2015-08-19 09:00:58 +09:00]] 版))
<http://www.w3.org/TR/2015/CR-tracking-dnt-20150820/>

[FIG(quote)[
[FIGCAPTION[
[46] [CITE[How we handle Do Not Track requests on Medium — Medium Policy — Medium]]
([[Medium]] 著, [TIME[2015-10-03 13:45:05 +09:00]] 版)
<https://medium.com/policy/how-we-handle-do-not-track-requests-on-medium-f2b4b4fb7c5e>
]FIGCAPTION]

> In order to explain this choice succinctly, we now show you the following message when you sign in to Medium with DNT settings enabled or in a private browser window:
> You have Do Not Track enabled, or are browsing privately. Medium respects your request for privacy: to read in stealth mode, stay logged out. While you are signed in, we collect some information about your interactions with the site in order to personalize your experience, offer suggested reading, and connect you with your network. More details can be found here.

]FIG]


[47] [CITE@en[Tracking Compliance and Scope]]
([TIME[2016-04-21 12:29:49 +09:00]] 版)
<https://www.w3.org/TR/2016/CR-tracking-compliance-20160426/>

[48] [CITE[Issue 989 - analytics-issues - Respect DNT (Do Not Track) and don't execute analytics.js - Google Analytics developer issues and feature requests - Google Project Hosting]]
( ([TIME[2017-01-10 21:41:47 +09:00]]))
<https://code.google.com/p/analytics-issues/issues/detail?id=989>

[50] [CITE@en-US[DNT - HTTP | MDN]]
([TIME[2017-03-18 05:10:49 +09:00]])
<https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/DNT>

[51] [CITE@en[628197 - (DNT) Implement do-not-track HTTP header]]
([TIME[2017-03-26 16:00:51 +09:00]])
<https://bugzilla.mozilla.org/show_bug.cgi?id=628197>

[52] [CITE@en[81844 - Implement Do Not Track - chromium - Monorail]]
([TIME[2017-03-26 16:02:09 +09:00]])
<https://bugs.chromium.org/p/chromium/issues/detail?id=81844>

[53] [CITE@en[draft-mayer-do-not-track-00 - Do Not Track: A Universal Third-Party Web Tracking Opt Out]]
([TIME[2017-03-19 19:13:15 +09:00]])
<https://tools.ietf.org/html/draft-mayer-do-not-track-00>

[54] [CITE@en[w3c/dnt: Issue-tracking for the TPWG specs]]
([TIME[2017-03-26 16:02:52 +09:00]])
<https://github.com/w3c/dnt>

[55] [CITE@en[DNT Implementing Site-Specific Consent]]
([TIME[2017-03-22 09:45:59 +09:00]])
<https://w3c.github.io/dnt/sitespecificconsent.html>

[56] [CITE@en[Using the API to specify DNT header extensions · Issue #20 · w3c/dnt]]
([TIME[2017-03-26 16:04:38 +09:00]])
<https://github.com/w3c/dnt/issues/20>

[57] [CITE@en[DNT API]]
([TIME[2017-03-22 09:45:59 +09:00]])
<https://w3c.github.io/dnt/dntapiwithpromises.html>

[58] [CITE@en-US[Do Not Track Consent API not working on Edge - Microsoft Edge Development]]
([TIME[2017-03-26 16:08:41 +09:00]])
<https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/7834877/>

[59] [CITE[public-tracking@w3.org Mail Archives]]
([TIME[2017-03-26 02:47:06 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/>

[60] [CITE@en[TPE editors draft has moved to github]]
([[Roy T. Fielding]]著, [TIME[2017-03-14 01:01:59 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Mar/0011.html>

[61] [CITE@en[Timeline to next CR (deadlines inside!)]]
([[Matthias Schunter (Intel Corporation)]]著, [TIME[2017-03-08 03:37:03 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Mar/0002.html>

[FIG(quote)[
[FIGCAPTION[
[62] [CITE@ja[Privacy Policy | Twitter]]
([TIME[2017-05-19 11:44:11 +09:00]])
<https://twitter.com/privacy?lang=ja>
]FIGCAPTION]

> Twitterは、ブラウザの「Do not Track (トラッキング拒否)」機能を尊重し、Twitterのユーザーエクスペリエンスや広告表示のカスタマイズにユーザーのウェブサイトアクセス情報がどのように使用されるかをユーザー自身が制御できるようにしています。

]FIG]


[FIG(quote)[
[FIGCAPTION[
[63] [CITE@ja[Do Not Track(トラッキング拒否) | Twitterヘルプセンター]]
([TIME[2017-05-19 11:44:34 +09:00]])
<https://support.twitter.com/articles/20171386#>
]FIGCAPTION]

> TwitterはDo Not Track(トラッキング拒否)のブラウザ設定のサポートを終了しました。業界におけるDo Not Trackの活用促進を目指してTwitterはDo Not Trackをサポートしていましたが、Do Not Trackに対する業界の足並みはそろいませんでした。

]FIG]


[FIG(quote)[
[FIGCAPTION[
[64] [CITE@ja[Twitterのプライバシーポリシーが新しくなりました | Twitterヘルプセンター]]
([TIME[2017-05-19 11:44:59 +09:00]])
<https://support.twitter.com/articles/20174639#>
]FIGCAPTION]

> 従来、Twitterではブラウザー設定「Do Not Track(トラッキング拒否)」を利用してきましたが、これらの新しい設定がトラッキング拒否に置き換わるため、今後はトラッキング拒否がサポートされなくなります。

]FIG]


[65] [CITE@ja[Twitter、主要ブラウザでの「Do Not Track」サポートを発表 - ITmedia エンタープライズ]]
(2012年05月18日 08時14分 更新 [TIME[2017-05-19 11:47:10 +09:00]])
<http://www.itmedia.co.jp/enterprise/articles/1205/18/news031.html>

[72] [CITE@en[Path to Candidate Recommendation in June; Please review and comment  draft by June 15. Call for objections is open until June 12.]]
([[Matthias Schunter (Intel Corporation)]]著, [TIME[2017-06-06 01:35:54 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Jun/0005.html>

[73] [CITE@ja[Mozilla Firefox ウェブブラウザー — Do Not Track — Mozilla]]
([TIME[2017-06-08 23:07:00 +09:00]])
<https://www.mozilla.org/ja/firefox/dnt/>

[FIG(quote)[
[FIGCAPTION[
[74] [CITE@ja[Microsoft、Webブラウザの「Do Not Track」をデフォルトで無効に - ITmedia NEWS]]
([TIME[2017-06-08 23:08:30 +09:00]])
<http://www.itmedia.co.jp/news/articles/1504/06/news036.html>
]FIGCAPTION]

> Microsoftは今回の方針変更について、「われわれの方針がW3Cの標準に準じていないのではないかという誤解を排除するため」と説明する。

]FIG]


[75] [CITE@ja[Microsoftは今後のブラウザ(IEとSpartan)で“Do Not Track”のoffをデフォルトにする | TechCrunch Japan]]
([[Frederic Lardinois]]著, [TIME[2017-06-08 23:08:45 +09:00]])
<http://jp.techcrunch.com/2015/04/04/20150403microsoft-disables-do-not-track-as-the-default-setting-in-internet-explorer/>

[76] [CITE@ja[Pinterest は「Do Not Track」機能に対応しています | ヘルプセンター]]
([TIME[2017-06-08 23:09:22 +09:00]])
<https://help.pinterest.com/ja/articles/we-support-do-not-track>

[77] [CITE@en[Call for Objections, Issue 22]]
([[Wendy Seltzer]]著, [TIME[2017-06-03 04:03:52 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Jun/0004.html>

[78] [CITE@en[status of Tracking Preference Expression (DNT) Editor's Draft]]
([[Roy T. Fielding]]著, [TIME[2017-07-02 23:24:18 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Jul/0000.html>

[79] [[Twitter]] の発表後もほとんど何の反応もなく開発が進められているのが興味深いwwww
重大プレイヤーが要求を満たせないと判断してるんだから、
仕様に致命的な欠陥があるのか、 [[Twitter]] が誤解してるのか、
はっきりさせたほうがいいんじゃないのかねぇ。

[80] しかし [[Webブラウザー事業者]]各社も、 [CODE[DNT:]] と 
[CODE[navigator.doNotTrack]] 以外の複雑な仕組みを実装する気はあるんですかねぇ。
仮に実装されたとして、[[Webアプリケーション]]事業者各社は使うんですかねぇ。
[[利用者]]はそれを理解できるんですかねぇ。

[81] [CITE@en-US[Navigator.doNotTrack - Web APIs | MDN]]
([TIME[2016-10-30 11:48:19 +09:00]])
<https://developer.mozilla.org/en-US/docs/Web/API/Navigator/doNotTrack>

[82] [CITE@en-US[DNT - HTTP | MDN]]
([TIME[2017-06-07 20:06:30 +09:00]])
<https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/DNT>

[83] [CITE@en[628197 - (DNT) Implement do-not-track HTTP header]]
([TIME[2017-07-12 18:44:13 +09:00]])
<https://bugzilla.mozilla.org/show_bug.cgi?id=628197>

[84] [CITE@en[751452 - DNT (DoNotTrack) header can be modified in XMLHttpRequest using setRequestHeader]]
([TIME[2017-07-12 18:44:33 +09:00]])
<https://bugzilla.mozilla.org/show_bug.cgi?id=751452>

[85] [CITE@en[630357 - The "Do Not Track" HTTP header is a server-side fingerprinting risk; turn it on by default or replace it with a JS flag]]
([TIME[2017-07-12 18:45:14 +09:00]])
<https://bugzilla.mozilla.org/show_bug.cgi?id=630357>

[86] [CITE@en[835357 - add telemetry to measure DNT usage]]
([TIME[2017-07-12 18:46:04 +09:00]])
<https://bugzilla.mozilla.org/show_bug.cgi?id=835357>

[87] [[Firefox Telemetry]] の [CODE[DNT_USAGE]]
を見ると、リリース版だと 25% くらいが [CODE[1]] に設定していて、
75% くらいが [CODE[0]] に設定していますね。未設定は 0% になっていますが、
たぶん既定値は未設定のはずなので、未設定ならデータが送られていないということでしょうか。
[TIME[2017-07-12T09:58:13.200Z]]

[FIG(quote)[
[FIGCAPTION[
[91] [CITE@en-US[Do you support Do Not Track (DNT)? – MailTracker Help]]
([TIME[2015-09-11 10:32:47 +09:00]])
<https://answerbook.zendesk.com/hc/en-us/articles/201493390-Do-you-support-Do-Not-Track-DNT->
]FIGCAPTION]

> However, having said that, most email apps (desktop clients) do not support any form of Do not track (DNT) but our systems are ready when that support is available.  DNT is primarily a web-based technology today and only really works with web-based email services (Yahoo, Outlook.com, etc.)
> A note about Gmail.  Google recently introduced an image proxy for Gmail's web-based email.  Google doesn't currently appear to pass the DNT header to us.  When this is available, our DNT support will kick in.
> Also in the future, we plan to add a facility on our website where people can opt out of all tracking by providing us their email address.  We hope to have this shortly.

]FIG]


[FIG(quote)[
[FIGCAPTION[
[92] [CITE@en_US[Legal Information | Smart House | momit]]
([[Iphonedroid]]著, [TIME[2017-07-12 19:10:11 +09:00]])
<https://www.momit.com/en-us/cookies>
]FIGCAPTION]

> momit has adapted its website to the standard Do Not Track to ensure privacy for users who have activated this option in your browser.

]FIG]


[FIG(quote)[
[FIGCAPTION[
[93] [CITE@ja[プライバシーポリシー | ウィズフルエンスは国際的なブランドとアジアの主要なインフルエンサーをつなぎ、アジアミレニアム世代へリーチを可能にするインフルエンサーマーケティングプラットフォームです]]
([TIME[2017-07-12 19:12:14 +09:00]])
<https://ja.withfluence.com/privacy_policy>
]FIGCAPTION]

> We honor do not track signals and do not track, plant cookies, or use advertising when a Do Not Track (DNT) browser mechanism is in place.

]FIG]


[FIG(quote)[
[FIGCAPTION[
[94] [CITE@en[Privacy | Symantec]]
([TIME[2017-07-12 18:47:37 +09:00]])
<https://www.symantec.com/privacy>
]FIGCAPTION]

> Please note that our websites may not recognize or take action in response to DNT signals from Web browsers. At this time, there is no universally accepted standard for what a company should do when a DNT signal is detected. In the event a final standard is established, we will assess how to appropriately respond to these signals.

]FIG]


[FIG(quote)[
[FIGCAPTION[
[95] [CITE@ja[Privacy Policy | 西大和学園補習校]]
([TIME[2017-07-12 19:17:34 +09:00]])
<https://www.nacus.org/hoshu/privacy-policy/>
]FIGCAPTION]

> We honor do not track signals and do not track, plant cookies, or use advertising when a Do Not Track (DNT) browser mechanism is in place.

]FIG]


[96] [CITE@en[today's ED status]]
([[Roy T. Fielding]]著, [TIME[2017-07-24 22:59:09 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Jul/0023.html>

[97] [CITE@en[Proposed Resolution / Consensus for Monday's call.]]
([[Matthias Schunter (Intel Corporation)]]著, [TIME[2017-08-25 23:30:35 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Aug/0040.html>

[98] [CITE@en[status of TPE as of August 30]]
([[Roy T. Fielding]]著, [TIME[2017-08-30 16:08:38 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Aug/0062.html>

[99] [CITE@en[Final Draft of TPE for Candidate Recommendation (respond by Sept 04)]]
([[Matthias Schunter (Intel Corporation)]]著, [TIME[2017-08-30 18:21:18 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Aug/0063.html>

[100] [CITE@en[Re: TPE latest]]
([[Roy T. Fielding]]著, [TIME[2017-08-31 09:49:28 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Aug/0072.html>

[101] [CITE@en[Tracking Preference Expression (DNT)]]
([TIME[2017-10-17 22:55:50 +09:00]])
<https://www.w3.org/TR/2017/CR-tracking-dnt-20171019/>

[102] [CITE@en[Status update from the W3C TPWG]]
([[Matthias Schunter (Intel Corporation)]]著, [TIME[2017-12-20 22:11:44 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Dec/0004.html>

[103] [CITE@en[DNT Implementation report]]
([TIME[2017-12-14 05:47:54 +09:00]])
<https://w3c.github.io/dnt/drafts/ImplementationReports.html>

[104] 基本機能以外を実装しているのは [[Edge]] だけで、
その [[Edge]] が実装しているのは古い [[API]] とかいう...
こんなので [[REC]] に進めるんですかね?
([[W3C]] の基準はがばがばなので進めても全然驚かないw)
[TIME[2018-01-12T02:46:13.700Z]]


[105] [CITE@en[Implementation phase - no calls for now]]
([[Matthias Schunter (Intel Corporation)]]著, [TIME[2017-11-21 17:58:34 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Nov/0025.html>

[106] [CITE@en[Pushing the current CR for TPE for REComenndation in 2017]]
([[Matthias Schunter (Intel Corporation)]]著, [TIME[2017-11-07 16:54:30 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Nov/0007.html>

[107] [CITE@en[Re: Pushing the current CR for TPE for REComenndation in 2017]]
([[Bert Bos]]著, [TIME[2017-11-09 09:41:34 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2017Nov/0010.html>

[108] [CITE@en[IAB-EU Consent framework and DNT]]
([[Mike O'Neill]]著, [TIME[2018-02-26 17:16:13 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2018Feb/0011.html>

[109] [CITE@en[Micro-Minutes / Next Call]]
([[Matthias Schunter (Intel Corporation)]]著, [TIME[2018-02-13 03:04:15 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2018Feb/0004.html>

[110] [CITE@en[RE: Micro-Minutes / Next Call]]
([[Mike O'Neill]]著, [TIME[2018-02-13 07:32:29 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2018Feb/0007.html>

[111] [CITE@en[w3c/dnt: Issue-tracking for the TPWG specs]]
([TIME[2018-09-21 22:55:44 +09:00]])
<https://github.com/w3c/dnt>

[FIG(quote)[
[FIGCAPTION[
[112] [CITE@en[Safari 12.1 Release Notes | Apple Developer Documentation]]
([TIME[2019-02-10 12:09:05 +09:00]])
<https://developer.apple.com/documentation/safari_release_notes/safari_12_1_release_notes>
]FIGCAPTION]

> Removed support for the expired Do Not Track standard to prevent potential use as a fingerprinting variable.

]FIG]


[113] [CITE@en[Tracking Protection Working Group now closed]]
([[xueyuan]]著, [TIME[2019-01-17 21:27:43 +09:00]])
<https://lists.w3.org/Archives/Public/public-tracking/2019Jan/0000.html>

[FIG(quote)[
[FIGCAPTION[
[114] [CITE@en[Tracking Preference Expression (DNT)]]
([TIME[2019-01-16 01:50:48 +09:00]])
<https://www.w3.org/TR/2019/NOTE-tracking-dnt-20190117/>
]FIGCAPTION]

> Since its last publication as a Candidate Recommendation, there has not been sufficient deployment of these extensions (as defined) to justify further advancement, nor have there been indications of planned support among user agents, third parties, and the ecosystem at large. The working group has therefore decided to conclude its work and republish the final product as this Note, with any future addendums to be published separately.

]FIG]


[115] [CITE@en[Tracking Compliance and Scope]]
([TIME[2019-01-19 00:57:42 +09:00]])
<https://www.w3.org/TR/tracking-compliance/>


[118] 
元の提案の [CODE[DNT:1]] / [CODE[DNT:0]] はまだ単純だったのに、
その他の謎の拡張や [[API]] が誰が何に使うのか意味不明だったしなー

[FIG(quote)[
[FIGCAPTION[
[119] [CITE@ja[はてなプライバシーポリシー - Hatena Policies]]
([TIME[2019-10-03 18:45:34 +09:00]])
<https://policies.hatena.ne.jp/privacypolicy-ja>
]FIGCAPTION]

> 3. はてなでは、ブラウザの「Do Not Track(トラッキング拒否)」 オプションをサポートしていません。

]FIG]