<s>
Email	B-Operating_System
tracking	I-Operating_System
is	O
a	O
method	O
for	O
monitoring	O
whether	O
the	O
email	O
messages	O
is	O
read	O
by	O
the	O
intended	O
recipient	O
.	O
</s>
<s>
Email	B-Operating_System
tracking	I-Operating_System
is	O
useful	O
for	O
when	O
the	O
sender	O
wants	O
to	O
know	O
whether	O
the	O
intended	O
recipient	O
actually	O
received	O
the	O
email	O
or	O
clicked	O
the	O
links	O
.	O
</s>
<s>
However	O
,	O
due	O
to	O
the	O
nature	O
of	O
the	O
technology	O
,	O
email	B-Operating_System
tracking	I-Operating_System
cannot	O
be	O
considered	O
an	O
absolutely	O
accurate	O
indicator	O
that	O
a	O
message	O
was	O
opened	O
or	O
read	O
by	O
the	O
recipient	O
.	O
</s>
<s>
Some	O
email	O
applications	O
,	O
such	O
as	O
Microsoft	B-Application
Office	I-Application
Outlook	I-Application
and	O
Mozilla	B-Application
Thunderbird	I-Application
,	O
employ	O
a	O
read-receipt	O
tracking	O
mechanism	O
.	O
</s>
<s>
Not	O
all	O
email	O
applications	O
or	O
services	O
support	O
sending	O
read	B-Operating_System
receipts	I-Operating_System
,	O
and	O
users	O
can	O
usually	O
disable	O
the	O
functionality	O
if	O
they	O
so	O
wish	O
.	O
</s>
<s>
Generally	O
,	O
read	B-Operating_System
receipts	I-Operating_System
are	O
only	O
useful	O
within	O
an	O
organization	O
where	O
all	O
mail	O
users	O
are	O
using	O
the	O
same	O
email	O
service	O
and	O
application	O
.	O
</s>
<s>
Read	B-Operating_System
receipts	I-Operating_System
are	O
sent	O
back	O
to	O
the	O
sender	O
's	O
"	O
inbox	O
"	O
as	O
email	O
messages	O
,	O
but	O
the	O
location	O
may	O
be	O
changed	O
depending	O
on	O
the	O
software	O
used	O
and	O
its	O
configuration	O
.	O
</s>
<s>
Several	O
email	B-Operating_System
tracking	I-Operating_System
services	O
also	O
feature	O
real-time	O
notifications	O
,	O
producing	O
an	O
on-screen	O
pop-up	O
whenever	O
the	O
sender	O
's	O
email	O
has	O
been	O
opened	O
.	O
</s>
<s>
Such	O
email	B-Operating_System
tracking	I-Operating_System
is	O
usually	O
accomplished	O
using	O
standard	O
web	B-Application
tracking	I-Application
devices	O
known	O
as	O
cookies	O
and	O
web	B-Protocol
beacons	I-Protocol
.	O
</s>
<s>
When	O
an	O
email	O
message	O
is	O
sent	O
,	O
if	O
it	O
is	O
a	O
graphical	O
HTML	O
message	O
(	O
not	O
a	O
plain	O
text	O
message	O
)	O
the	O
email	O
marketing	O
system	O
may	O
embed	O
a	O
tiny	O
,	O
invisible	O
tracking	O
image	O
(	O
a	O
single-pixel	O
gif	O
,	O
sometimes	O
called	O
a	O
web	B-Protocol
beacon	I-Protocol
)	O
within	O
the	O
content	O
of	O
the	O
message	O
.	O
</s>
<s>
Email	B-Operating_System
tracking	I-Operating_System
services	O
may	O
also	O
offer	O
collations	O
of	O
tracked	O
data	O
,	O
allowing	O
users	O
to	O
analyze	O
the	O
statistics	O
of	O
their	O
email	O
performance	O
.	O
</s>
<s>
Email	B-Operating_System
tracking	I-Operating_System
is	O
used	O
by	O
individuals	O
including	O
email	O
marketers	O
,	O
spammers	O
and	O
phishers	O
to	O
verify	O
that	O
emails	O
are	O
actually	O
read	O
by	O
recipients	O
,	O
that	O
email	O
addresses	O
are	O
valid	O
,	O
and	O
that	O
the	O
content	O
of	O
emails	O
has	O
made	O
it	O
past	O
spam	O
filters	O
.	O
</s>
<s>
The	O
tracking	O
mechanisms	O
employed	O
are	O
typically	O
first-party	O
cookies	O
and	O
web	B-Protocol
beacons	I-Protocol
.	O
</s>
<s>
HP	O
said	O
they	O
consider	O
email	B-Operating_System
tracking	I-Operating_System
to	O
be	O
legitimate	O
and	O
will	O
continue	O
using	O
it	O
.	O
</s>
