<s>
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
(	O
DNT	O
)	O
is	O
a	O
formerly	O
official	O
HTTP	B-Protocol
header	I-Protocol
field	I-Protocol
,	O
designed	O
to	O
allow	O
internet	O
users	O
to	O
opt-out	O
of	O
tracking	B-Application
by	O
websites	O
—	O
which	O
includes	O
the	O
collection	O
of	O
data	O
regarding	O
a	O
user	O
's	O
activity	O
across	O
multiple	O
distinct	O
contexts	O
,	O
and	O
the	O
retention	O
,	O
use	O
,	O
or	O
sharing	O
of	O
data	O
derived	O
from	O
that	O
activity	O
outside	O
the	O
context	O
in	O
which	O
it	O
occurred	O
.	O
</s>
<s>
The	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
header	I-Protocol
was	O
originally	O
proposed	O
in	O
2009	O
by	O
researchers	O
Christopher	O
Soghoian	O
,	O
Sid	O
Stamm	O
,	O
and	O
Dan	O
Kaminsky	O
.	O
</s>
<s>
Mozilla	B-Application
Firefox	I-Application
became	O
the	O
first	O
browser	O
to	O
implement	O
the	O
feature	O
,	O
while	O
Internet	B-Application
Explorer	I-Application
,	O
Apple	B-Application
's	I-Application
Safari	I-Application
,	O
Opera	B-Application
and	O
Google	B-Application
Chrome	I-Application
all	O
later	O
added	O
support	O
.	O
</s>
<s>
Efforts	O
to	O
standardize	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
by	O
the	O
W3C	O
in	O
the	O
Tracking	B-Application
Preference	O
Expression	O
(	O
DNT	O
)	O
Working	O
Group	O
reached	O
only	O
the	O
Candidate	O
Recommendation	O
stage	O
and	O
ended	O
in	O
September	O
2018	O
due	O
to	O
insufficient	O
deployment	O
and	O
support	O
.	O
</s>
<s>
DNT	O
is	O
not	O
widely	O
adopted	O
by	O
the	O
industry	O
,	O
with	O
companies	O
citing	O
the	O
lack	O
of	O
legal	O
mandates	O
for	O
its	O
use	O
,	O
(	O
see	O
Do	B-Application
Not	I-Application
Track	I-Application
legislation	I-Application
)	O
as	O
well	O
as	O
unclear	O
standards	O
and	O
guidelines	O
for	O
how	O
websites	O
are	O
to	O
interpret	O
the	O
header	O
.	O
</s>
<s>
Apple	O
discontinued	O
support	O
for	O
DNT	O
the	O
following	O
month	O
,	O
citing	O
browser	B-Protocol
fingerprinting	I-Protocol
concerns	O
.	O
</s>
<s>
As	O
of	O
March	O
2023	O
,	O
Mozilla	B-Application
Firefox	I-Application
continues	O
to	O
support	O
DNT	O
,	O
where	O
it	O
is	O
turned	O
on	O
by	O
default	O
in	O
private	B-Protocol
browsing	I-Protocol
mode	O
and	O
optional	O
in	O
regular	O
mode	O
.	O
</s>
<s>
In	O
2020	O
,	O
a	O
coalition	O
of	O
US-based	O
internet	O
companies	O
announced	O
the	O
Global	O
Privacy	O
Control	O
header	O
that	O
spiritually	O
succeeds	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
header	I-Protocol
.	O
</s>
<s>
In	O
2007	O
,	O
several	O
consumer	O
advocacy	O
groups	O
asked	O
the	O
U.S.	O
Federal	O
Trade	O
Commission	O
to	O
create	O
a	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
list	O
for	O
online	O
advertising	O
.	O
</s>
<s>
In	O
July	O
2009	O
,	O
researchers	O
Christopher	O
Soghoian	O
and	O
Sid	O
Stamm	O
created	O
a	O
prototype	O
add-on	O
for	O
the	O
Firefox	B-Application
web	I-Application
browser	I-Application
,	O
implementing	O
support	O
for	O
the	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
header	I-Protocol
.	O
</s>
<s>
Stamm	O
was	O
,	O
at	O
the	O
time	O
,	O
a	O
privacy	O
engineer	O
at	O
Mozilla	B-Operating_System
,	O
while	O
Soghoian	O
soon	O
afterward	O
started	O
working	O
at	O
the	O
FTC	O
.	O
</s>
<s>
One	O
year	O
later	O
,	O
during	O
a	O
U.S.	O
Senate	O
privacy	O
hearing	O
,	O
FTC	O
Chairman	O
Jon	O
Leibowitz	O
told	O
the	O
Senate	O
Commerce	O
Committee	O
that	O
the	O
commission	O
was	O
exploring	O
the	O
idea	O
of	O
proposing	O
a	O
"	O
do-not-track	B-Protocol
"	O
list	O
.	O
</s>
<s>
In	O
December	O
2010	O
,	O
the	O
FTC	O
issued	O
a	O
privacy	O
report	O
that	O
called	O
for	O
a	O
"	O
do	B-Protocol
not	I-Protocol
track	I-Protocol
"	O
system	O
that	O
would	O
enable	O
people	O
to	O
avoid	O
having	O
their	O
actions	O
being	O
monitored	O
online	O
.	O
</s>
<s>
One	O
week	O
later	O
,	O
Microsoft	O
announced	O
that	O
its	O
next	O
browser	O
would	O
include	O
support	O
for	O
Tracking	B-Application
Protection	O
Lists	O
that	O
block	O
tracking	B-Application
of	O
consumers	O
using	O
blacklists	O
supplied	O
by	O
third	O
parties	O
.	O
</s>
<s>
In	O
January	O
2011	O
,	O
Mozilla	B-Operating_System
announced	O
that	O
its	O
Firefox	B-Application
browser	I-Application
would	O
soon	O
provide	O
a	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
solution	O
,	O
via	O
a	O
browser	O
header	O
.	O
</s>
<s>
Microsoft	O
's	O
Internet	B-Application
Explorer	I-Application
9	I-Application
,	O
</s>
<s>
Apple	B-Application
's	I-Application
Safari	I-Application
,	O
Opera	B-Application
and	O
Google	B-Application
Chrome	I-Application
all	O
later	O
added	O
support	O
for	O
the	O
header	O
approach	O
.	O
</s>
<s>
In	O
August	O
2015	O
a	O
coalition	O
of	O
privacy	O
groups	O
led	O
by	O
the	O
Electronic	O
Frontier	O
Foundation	O
using	O
W3C	O
's	O
Tracking	B-Application
Preference	O
Expression	O
(	O
DNT	O
)	O
standard	O
proposed	O
that	O
"	O
Do	B-Protocol
not	I-Protocol
track	I-Protocol
"	O
be	O
the	O
goal	O
for	O
advocates	O
to	O
demand	O
of	O
businesses	O
.	O
</s>
<s>
In	O
January	O
2019	O
,	O
the	O
W3C	O
Tracking	B-Application
Protection	O
Working	O
Group	O
was	O
disbanded	O
,	O
citing	O
"	O
insufficient	O
deployment	O
of	O
these	O
extensions	O
"	O
and	O
lack	O
of	O
"	O
indications	O
of	O
planned	O
support	O
among	O
user	O
agents	O
,	O
third	O
parties	O
,	O
and	O
the	O
ecosystem	O
at	O
large.	O
"	O
</s>
<s>
Beginning	O
the	O
following	O
month	O
,	O
Apple	O
removed	O
DNT	O
support	O
from	O
Safari	B-Application
,	O
citing	O
that	O
it	O
could	O
be	O
used	O
as	O
a	O
"	O
fingerprinting	B-Protocol
variable	O
"	O
for	O
tracking	B-Application
.	O
</s>
<s>
When	O
using	O
the	O
"	O
Express	O
"	O
settings	O
upon	O
installation	O
,	O
a	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
option	O
is	O
enabled	O
by	O
default	O
for	O
Internet	B-Application
Explorer	I-Application
10	I-Application
and	O
Windows	B-Application
8	I-Application
.	O
</s>
<s>
Microsoft	O
faced	O
criticism	O
for	O
its	O
decision	O
to	O
enable	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
by	O
default	O
from	O
advertising	O
companies	O
,	O
who	O
say	O
that	O
use	O
of	O
the	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
header	I-Protocol
should	O
be	O
a	O
choice	O
made	O
by	O
the	O
user	O
and	O
must	O
not	O
be	O
automatically	O
enabled	O
.	O
</s>
<s>
The	O
companies	O
also	O
said	O
that	O
this	O
decision	O
would	O
violate	O
the	O
Digital	O
Advertising	O
Alliance	O
's	O
agreement	O
with	O
the	O
U.S.	O
government	O
to	O
honor	O
a	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
system	O
,	O
because	O
the	O
coalition	O
said	O
it	O
would	O
only	O
honor	O
such	O
a	O
system	O
if	O
it	O
were	O
not	O
enabled	O
by	O
default	O
by	O
web	O
browsers	O
.	O
</s>
<s>
On	O
September	O
7	O
,	O
2012	O
,	O
Roy	O
Fielding	O
,	O
an	O
author	O
of	O
the	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
standard	O
,	O
committed	B-Protocol
a	O
patch	O
to	O
the	O
source	O
code	O
of	O
the	O
Apache	B-Application
HTTP	I-Application
Server	I-Application
,	O
which	O
would	O
make	O
the	O
server	O
explicitly	O
ignore	O
any	O
use	O
of	O
the	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
header	I-Protocol
by	O
users	O
of	O
Internet	B-Application
Explorer	I-Application
10	I-Application
.	O
</s>
<s>
Fielding	O
wrote	O
that	O
Microsoft	O
's	O
decision	O
"	O
deliberately	O
violates	O
"	O
the	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
specification	O
because	O
it	O
"	O
does	O
not	O
protect	O
anyone	O
's	O
privacy	O
unless	O
the	O
recipients	O
believe	O
it	O
was	O
set	O
by	O
a	O
real	O
human	O
being	O
,	O
with	O
a	O
real	O
preference	O
for	O
privacy	O
over	O
personalization	O
"	O
.	O
</s>
<s>
The	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
specification	O
did	O
not	O
explicitly	O
mandate	O
that	O
the	O
use	O
of	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
actually	O
be	O
a	O
choice	O
until	O
after	O
the	O
feature	O
was	O
implemented	O
in	O
Internet	B-Application
Explorer	I-Application
10	I-Application
.	O
</s>
<s>
According	O
to	O
Fielding	O
,	O
Microsoft	O
knew	O
its	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
signals	O
would	O
be	O
ignored	O
,	O
and	O
that	O
its	O
goal	O
was	O
to	O
effectively	O
give	O
an	O
illusion	O
of	O
privacy	O
while	O
still	O
catering	O
to	O
their	O
own	O
interests	O
.	O
</s>
<s>
On	O
April	O
3	O
,	O
2015	O
,	O
Microsoft	O
announced	O
that	O
starting	O
with	O
Windows	B-Operating_System
10	I-Operating_System
,	O
it	O
would	O
comply	O
with	O
the	O
specification	O
and	O
no	O
longer	O
automatically	O
enable	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
as	O
part	O
of	O
the	O
operating	O
system	O
's	O
"	O
Express	O
"	O
default	O
settings	O
,	O
but	O
that	O
the	O
company	O
will	O
"	O
provide	O
customers	O
with	O
clear	O
information	O
on	O
how	O
to	O
turn	O
this	O
feature	O
on	O
in	O
the	O
browser	O
settings	O
should	O
they	O
wish	O
to	O
do	O
so	O
"	O
.	O
</s>
<s>
Websites	O
that	O
honor	O
DNT	O
requests	O
include	O
Medium	B-Protocol
and	O
Pinterest	B-Application
.	O
</s>
<s>
Despite	O
offering	O
the	O
option	O
in	O
its	O
Chrome	B-Application
web	I-Application
browser	I-Application
,	O
Google	B-Application
did	O
not	O
implement	O
support	O
for	O
DNT	O
on	O
its	O
websites	O
,	O
and	O
directed	O
users	O
to	O
its	O
online	O
privacy	O
settings	O
and	O
opt-outs	O
for	O
interest-based	O
advertising	O
instead	O
.	O
</s>
<s>
Use	O
of	O
ad	O
blocking	O
software	O
to	O
block	O
web	O
trackers	O
and	O
advertising	O
has	O
become	O
increasingly	O
common	O
(	O
with	O
users	O
citing	O
both	O
privacy	O
concerns	O
and	O
performance	O
impact	O
as	O
justification	O
)	O
,	O
while	O
Apple	O
and	O
Mozilla	B-Operating_System
began	O
to	O
add	O
privacy	O
enhancements	O
(	O
such	O
as	O
"	O
tracking	B-Application
protection	O
"	O
)	O
to	O
their	O
browsers	O
,	O
that	O
are	O
designed	O
to	O
reduce	O
undue	O
cross-site	B-Application
tracking	I-Application
.	O
</s>
<s>
Global	O
Privacy	O
Control	O
(	O
GPC	O
)	O
is	O
a	O
proposed	O
HTTP	B-Protocol
header	I-Protocol
field	I-Protocol
and	O
DOM	B-General_Concept
property	O
that	O
can	O
be	O
used	O
to	O
inform	O
websites	O
of	O
the	O
user	O
's	O
wish	O
to	O
have	O
their	O
information	O
not	O
be	O
sold	O
or	O
used	O
by	O
ad	O
trackers	O
.	O
</s>
<s>
GPC	O
was	O
developed	O
in	O
2020	O
by	O
privacy	O
technology	O
researchers	O
such	O
as	O
Wesleyan	O
University	O
professor	O
Sebastian	O
Zimmeck	O
and	O
former	O
Chief	O
Technologist	O
of	O
the	O
Federal	O
Trade	O
Commission	O
Ashkan	O
Soltani	O
,	O
as	O
well	O
as	O
a	O
group	O
of	O
privacy-focused	O
companies	O
including	O
the	O
Electronic	O
Frontier	O
Foundation	O
,	O
Automattic	O
(	O
owner	O
of	O
Tumblr	B-Application
and	O
WordPress	B-Application
)	O
,	O
and	O
more	O
.	O
</s>
<s>
The	O
signal	O
has	O
been	O
implemented	O
by	O
DuckDuckGo	B-Application
's	O
privacy	O
extension	O
,	O
The	O
New	O
York	O
Times	O
,	O
and	O
privacy	O
browser	O
Brave	B-Application
and	O
is	O
supported	O
by	O
Firefox	B-Application
creator	O
,	O
Mozilla	B-Operating_System
as	O
well	O
as	O
former	O
California	O
Attorney	O
General	O
Xavier	O
Becerra	O
.	O
</s>
<s>
GPC	O
is	O
a	O
spiritual	O
successor	O
to	O
the	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
header	I-Protocol
that	O
was	O
created	O
in	O
2009	O
but	O
did	O
n't	O
find	O
widespread	O
success	O
due	O
to	O
the	O
lack	B-Application
of	I-Application
legislation	I-Application
that	O
would	O
require	O
companies	O
to	O
legally	O
respect	O
the	O
Do	B-Protocol
Not	I-Protocol
Track	I-Protocol
header	I-Protocol
.	O
</s>
