<s>
Cross-device	B-Application
tracking	I-Application
refers	O
to	O
technology	O
that	O
enables	O
the	O
tracking	O
of	O
users	O
across	O
multiple	O
devices	O
such	O
as	O
smartphones	B-Application
,	O
television	O
sets	O
,	O
smart	O
TVs	O
,	O
and	O
personal	O
computers	O
.	O
</s>
<s>
More	O
specifically	O
,	O
cross-device	B-Application
tracking	I-Application
is	O
a	O
technique	O
in	O
which	O
technology	O
companies	O
and	O
advertisers	O
deploy	O
trackers	O
,	O
often	O
in	O
the	O
form	O
of	O
unique	O
identifiers	O
,	O
cookies	B-Application
,	O
or	O
even	O
ultrasonic	O
signals	O
,	O
to	O
generate	O
a	O
profile	B-Algorithm
of	O
users	O
across	O
multiple	O
devices	O
,	O
not	O
simply	O
one	O
.	O
</s>
<s>
For	O
example	O
,	O
one	O
such	O
form	O
of	O
this	O
tracking	O
uses	O
audio	B-Application
beacons	I-Application
,	O
or	O
inaudible	O
sounds	O
,	O
emitted	O
by	O
one	O
device	O
and	O
recognized	O
through	O
the	O
microphone	O
of	O
the	O
other	O
device	O
.	O
</s>
<s>
This	O
form	O
of	O
tracking	O
is	O
used	O
primarily	O
by	O
technology	O
companies	O
and	O
advertisers	O
who	O
use	O
this	O
information	O
to	O
piece	O
together	O
a	O
cohesive	O
profile	B-Algorithm
of	O
the	O
user	O
.	O
</s>
<s>
There	O
are	O
many	O
ways	O
in	O
which	O
online	B-Application
tracking	I-Application
has	O
manifested	O
itself	O
.	O
</s>
<s>
This	O
is	O
a	O
form	O
of	O
deterministic	O
cross-device	B-Application
tracking	I-Application
,	O
in	O
which	O
the	O
user	O
's	O
devices	O
are	O
associated	O
with	O
their	O
account	O
credentials	O
,	O
such	O
as	O
their	O
email	O
or	O
username	O
.	O
</s>
<s>
Eventually	O
,	O
cookies	B-Application
were	O
deployed	O
by	O
advertisers	O
,	O
providing	O
each	O
user	O
with	O
a	O
unique	O
identifier	O
in	O
his	O
or	O
her	O
browser	O
so	O
that	O
the	O
user	O
's	O
preferences	O
can	O
be	O
monitored	O
.	O
</s>
<s>
Cookies	B-Application
were	O
also	O
used	O
by	O
companies	O
to	O
improve	O
the	O
user	O
experience	O
,	O
enabling	O
users	O
to	O
pick	O
up	O
where	O
they	O
left	O
off	O
on	O
websites	O
.	O
</s>
<s>
However	O
,	O
as	O
users	O
began	O
using	O
multiple	O
devices	O
–	O
–	O
up	O
to	O
around	O
five	O
–	O
–	O
advertisers	O
became	O
confused	O
as	O
to	O
how	O
to	O
track	O
,	O
manage	O
,	O
and	O
consolidate	O
this	O
data	O
across	O
multiple	O
devices	O
as	O
the	O
cookie-based	O
model	O
suggested	O
that	O
each	O
device	O
–	O
–	O
whether	O
a	O
phone	O
,	O
computer	O
,	O
or	O
tablet	O
–	O
–	O
was	O
a	O
different	O
person	O
.	O
</s>
<s>
Other	O
technologies	O
such	O
as	O
supercookies	B-Application
,	O
which	O
stay	O
on	O
computers	O
long	O
after	O
the	O
user	O
deletes	O
his	O
or	O
her	O
cookies	B-Application
,	O
and	O
web	B-Protocol
beacons	I-Protocol
,	O
which	O
are	O
unique	O
images	O
from	O
a	O
URL	O
,	O
are	O
also	O
used	O
by	O
trackers	O
and	O
advertisers	O
to	O
gain	O
increased	O
insight	O
into	O
users	O
 '	O
behavior	O
.	O
</s>
<s>
Thus	O
,	O
cross-device	B-Application
tracking	I-Application
initially	O
emerged	O
as	O
a	O
means	O
of	O
generating	O
a	O
profile	B-Algorithm
of	O
users	O
across	O
multiple	O
devices	O
,	O
not	O
simply	O
one	O
.	O
</s>
<s>
One	O
such	O
tactic	O
for	O
cross-device	B-Application
tracking	I-Application
is	O
called	O
browser	B-Protocol
fingerprinting	I-Protocol
,	O
and	O
occurs	O
when	O
browsers	O
,	O
which	O
are	O
modifiable	O
to	O
the	O
users	O
 '	O
tastes	O
,	O
produce	O
a	O
unique	O
signal	O
that	O
companies	O
or	O
advertisers	O
can	O
use	O
to	O
single	O
out	O
the	O
user	O
.	O
</s>
<s>
Browser	B-Protocol
fingerprinting	I-Protocol
has	O
been	O
a	O
cause	O
for	O
concern	O
because	O
of	O
its	O
effectiveness	O
and	O
also	O
since	O
it	O
does	O
not	O
allow	O
for	O
users	O
to	O
opt-out	O
of	O
the	O
tracking	O
.	O
</s>
<s>
Another	O
tactic	O
used	O
by	O
Google	O
is	O
called	O
AdID	O
and	O
works	O
on	O
smartphones	B-Application
in	O
tandem	O
with	O
cookies	B-Application
on	O
a	O
user	O
's	O
computer	O
to	O
track	O
behavior	O
across	O
devices	O
.	O
</s>
<s>
Now	O
,	O
cross-device	B-Application
tracking	I-Application
has	O
evolved	O
into	O
a	O
new	O
,	O
radical	O
form	O
of	O
surveillance	O
technology	O
which	O
enables	O
users	O
to	O
be	O
tracked	O
across	O
multiple	O
devices	O
,	O
including	O
smartphones	B-Application
,	O
TVs	O
,	O
and	O
personal	O
computers	O
through	O
the	O
use	O
of	O
audio	B-Application
beacons	I-Application
,	O
or	O
inaudible	O
sound	O
,	O
emitted	O
by	O
one	O
device	O
and	O
recognized	O
through	O
the	O
microphone	O
of	O
the	O
other	O
device	O
,	O
usually	O
a	O
smartphone	B-Application
.	O
</s>
<s>
In	O
addition	O
,	O
cross-device	B-Application
tracking	I-Application
may	O
presage	O
the	O
future	O
of	O
the	B-Operating_System
Internet	I-Operating_System
of	I-Operating_System
things	I-Operating_System
(	O
IoT	B-Operating_System
)	O
,	O
in	O
which	O
all	O
types	O
of	O
devices	O
–	O
–	O
such	O
as	O
offices	O
,	O
cars	O
,	O
and	O
homes	O
–	O
–	O
are	O
seamlessly	O
interconnected	O
via	O
the	O
internet	O
.	O
</s>
<s>
Ultrasound	B-Application
,	O
which	O
is	O
shorter	O
wavelengths	O
greater	O
than	O
or	O
equal	O
to	O
20kHz	O
,	O
enables	O
the	O
rapid	O
transmission	O
of	O
data	O
necessary	O
for	O
cross-device	B-Application
tracking	I-Application
to	O
occur	O
.	O
</s>
<s>
Another	O
integral	O
component	O
of	O
cross-device	B-Application
tracking	I-Application
is	O
the	O
usage	O
of	O
audio	B-Application
beacons	I-Application
.	O
</s>
<s>
Audio	B-Application
beacons	I-Application
are	O
beacons	B-Protocol
that	O
are	O
embedded	O
into	O
ultrasound	B-Application
,	O
so	O
they	O
cannot	O
be	O
heard	O
by	O
humans	O
.	O
</s>
<s>
These	O
audio	B-Application
beacons	I-Application
are	O
used	O
to	O
surreptitiously	O
track	O
a	O
user	O
's	O
location	O
and	O
monitor	O
online	O
behavior	O
by	O
connecting	O
with	O
the	O
microphone	O
on	O
another	O
device	O
without	O
the	O
user	O
's	O
awareness	O
.	O
</s>
<s>
In	O
October	O
2015	O
,	O
the	O
Center	O
for	O
Democracy	O
and	O
Technology	O
submitted	O
comments	O
to	O
the	O
Federal	O
Trade	O
Commission	O
(	O
FTC	O
)	O
regarding	O
cross-device	B-Application
tracking	I-Application
technology	O
,	O
specifically	O
mentioning	O
SilverPush	B-Application
.	O
</s>
<s>
Audio	O
"	O
beacons	B-Protocol
"	O
can	O
be	O
embedded	O
into	O
television	O
advertisements	O
.	O
</s>
<s>
In	O
a	O
similar	O
manner	O
to	O
radio	O
beacons	B-Protocol
,	O
these	O
can	O
be	O
picked	O
up	O
by	O
mobile	B-Application
apps	I-Application
.	O
</s>
<s>
In	O
March	O
2016	O
,	O
the	O
FTC	O
issued	O
warning	O
letters	O
to	O
12	O
app	O
developers	O
using	O
cross-device	B-Application
tracking	I-Application
in	O
their	O
apps	O
.	O
</s>
<s>
Studies	O
have	O
shown	O
that	O
234	O
Android	B-Application
applications	I-Application
are	O
eavesdropping	O
on	O
these	O
ultrasonic	O
channels	O
without	O
the	O
user	O
's	O
awareness	O
.	O
</s>
<s>
Applications	O
such	O
as	O
SilverPush	B-Application
,	O
Shopkick	O
,	O
and	O
Lisnr	O
are	O
part	O
of	O
an	O
"	O
ultrasonic	O
side-channel	O
"	O
in	O
which	O
the	O
app	O
,	O
often	O
unbeknownst	O
to	O
the	O
user	O
,	O
intercepts	O
ultrasonic	O
signals	O
emitted	O
from	O
the	O
user	O
's	O
environment	O
,	O
such	O
as	O
from	O
a	O
TV	O
,	O
to	O
track	O
which	O
advertisements	O
the	O
user	O
has	O
heard	O
and	O
how	O
long	O
the	O
person	O
listened	O
to	O
them	O
.	O
</s>
<s>
Another	O
study	O
suggested	O
that	O
Apple	O
,	O
Google	O
,	O
and	O
Bluetooth	O
Special	O
Interest	O
groups	O
need	O
to	O
do	O
more	O
to	O
prevent	O
cross-device	B-Application
tracking	I-Application
.	O
</s>
<s>
Cross-device	B-Application
tracking	I-Application
has	O
privacy	O
implications	O
and	O
allows	O
for	O
more	O
detailed	O
tracking	O
of	O
users	O
than	O
traditional	O
tracking	O
methods	O
.	O
</s>
<s>
Another	O
form	O
of	O
tracking	O
permitted	O
by	O
ultrasonic	O
tracking	O
is	O
cross-device	B-Application
tracking	I-Application
,	O
which	O
enables	O
a	O
user	O
's	O
profile	B-Algorithm
to	O
be	O
connected	O
across	O
multiple	O
devices	O
based	O
on	O
proximity	O
.	O
</s>
<s>
Lastly	O
,	O
this	O
new	O
ultrasonic	O
tracking	O
poses	O
a	O
threat	O
to	O
users	O
of	O
Bitcoin	B-Protocol
and	O
Tor	B-Application
because	O
it	O
de-anonymizes	O
a	O
user	O
's	O
information	O
,	O
since	O
ultrasonic	O
signals	O
associate	O
the	O
user	O
's	O
mobile	O
phone	O
with	O
the	O
Bitcoin	B-Protocol
or	O
Tor	B-Application
account	O
.	O
</s>
<s>
From	O
cookies	B-Application
to	O
ultrasonic	O
trackers	O
,	O
some	O
argue	O
that	O
invasive	O
forms	O
of	O
surveillance	O
underscore	O
how	O
users	O
are	O
trapped	O
in	O
a	O
digital	O
panopticon	B-Application
,	O
similar	O
to	O
the	O
concept	O
envisioned	O
by	O
Jeremy	O
Bentham	O
:	O
a	O
prison	O
in	O
which	O
the	O
prisoners	O
were	O
able	O
to	O
be	O
seen	O
at	O
all	O
times	O
by	O
guards	O
but	O
were	O
unable	O
to	O
detect	O
when	O
,	O
or	O
even	O
if	O
,	O
they	O
were	O
being	O
watched	O
at	O
all	O
,	O
creating	O
a	O
sense	O
of	O
paranoia	O
that	O
drove	O
prisoners	O
to	O
carefully	O
police	O
their	O
own	O
behavior	O
.	O
</s>
<s>
Similarly	O
,	O
scholars	O
have	O
drawn	O
parallels	O
between	O
Bentham	O
's	O
panopticon	B-Application
and	O
today	O
's	O
pervasive	O
use	O
of	O
internet	O
tracking	O
in	O
that	O
individuals	O
lack	O
awareness	O
to	O
the	O
vast	O
disparities	O
of	O
power	O
that	O
exist	O
between	O
themselves	O
and	O
the	O
corporation	O
to	O
which	O
they	O
willingly	O
give	O
their	O
data	O
.	O
</s>
<s>
The	O
television	O
,	O
along	O
with	O
the	O
remote	O
control	O
,	O
is	O
also	O
argued	O
to	O
be	O
conditioning	O
humans	O
into	O
habitually	O
repeating	O
that	O
which	O
they	O
enjoy	O
without	O
experiencing	O
genuine	O
surprise	O
or	O
even	O
discomfort	O
,	O
a	O
critique	O
of	O
the	O
television	O
similar	O
to	O
that	O
of	O
those	O
made	O
against	O
information	B-Application
silos	I-Application
on	O
social	O
media	O
sites	O
today	O
.	O
</s>
<s>
Plus	O
,	O
companies	O
like	O
TiVO	O
analyze	O
how	O
TV	O
show	O
watchers	O
use	O
their	O
remote	O
and	O
DVR	B-Application
capability	O
to	O
skip	O
over	O
programming	O
,	O
such	O
as	O
advertisements	O
–	O
–	O
a	O
privacy	O
concern	O
users	O
may	O
lack	O
awareness	O
of	O
as	O
well	O
.	O
</s>
<s>
Increasingly	O
,	O
users	O
 '	O
digital	B-Application
identity	I-Application
is	O
becoming	O
commodified	O
through	O
the	O
selling	O
and	O
monetizing	O
of	O
their	O
personal	O
data	O
for	O
profit	O
by	O
large	O
companies	O
.	O
</s>
<s>
The	O
increased	O
usage	O
of	O
cross-device	B-Application
tracking	I-Application
by	O
advertisers	O
is	O
indicative	O
of	O
the	O
rise	O
of	O
a	O
new	O
era	O
of	O
data	O
extraction	O
and	O
analysis	O
as	O
a	O
form	O
of	O
profit	O
,	O
or	O
surveillance	B-General_Concept
capitalism	I-General_Concept
,	O
a	O
term	O
coined	O
by	O
Shoshana	O
Zuboff	O
.	O
</s>
<s>
Zuboff	O
suggests	O
that	O
this	O
new	O
era	O
of	O
surveillance	B-General_Concept
capitalism	I-General_Concept
eclipses	O
Bentham	O
's	O
panopticon	B-Application
,	O
becoming	O
far	O
more	O
encroaching	O
and	O
invasive	O
as	O
,	O
unlike	O
a	O
prison	O
,	O
there	O
is	O
no	O
escape	O
,	O
and	O
the	O
thoughts	O
,	O
feelings	O
,	O
and	O
actions	O
of	O
users	O
are	O
immediately	O
extracted	O
to	O
be	O
commodified	O
and	O
resold	O
.	O
</s>
<s>
Thus	O
,	O
since	O
cross-device	B-Application
tracking	I-Application
seeks	O
to	O
create	O
a	O
profile	B-Algorithm
of	O
a	O
user	O
across	O
multiple	O
devices	O
,	O
big	O
tech	O
companies	O
,	O
such	O
as	O
Google	O
,	O
could	O
use	O
this	O
behavioral	O
data	O
to	O
make	O
predictions	O
about	O
the	O
user	O
's	O
future	O
behavior	O
without	O
the	O
user	O
's	O
awareness	O
.	O
</s>
<s>
The	O
lack	O
of	O
adequate	O
privacy	O
and	O
security	O
measures	O
surrounding	O
users	O
 '	O
personal	O
medical	O
data	O
on	O
mobile	B-Application
applications	I-Application
underscores	O
the	O
lessening	O
degree	O
to	O
which	O
users	O
can	O
trust	O
mobile	B-Application
app	I-Application
developers	O
to	O
safeguard	O
their	O
personal	O
information	O
online	O
.	O
</s>
<s>
While	O
mobile	B-Application
application	I-Application
developers	O
continue	O
to	O
confront	O
privacy	O
and	O
security	O
concerns	O
,	O
users	O
are	O
increasingly	O
looking	O
to	O
ways	O
to	O
visualize	O
their	O
data	O
through	O
wearable	O
devices	O
and	O
applications	O
that	O
track	O
their	O
workout	O
and	O
exercise	O
routines	O
.	O
</s>
<s>
Additionally	O
,	O
privacy	O
concerns	O
surround	O
cookies	B-Application
,	O
flash	O
cookies	B-Application
,	O
and	O
web	B-Protocol
beacons	I-Protocol
on	O
websites	O
today	O
.	O
</s>
<s>
Ultimately	O
,	O
five	O
main	O
concerns	O
surround	O
the	O
usage	O
of	O
cookies	B-Application
,	O
flash	O
cookies	B-Application
,	O
and	O
web	B-Protocol
beacons	I-Protocol
,	O
according	O
to	O
a	O
study	O
:	O
</s>
<s>
There	O
are	O
three	O
fundamental	O
theories	O
of	O
how	O
large	O
companies	O
engage	O
users	O
in	O
virtual	B-Architecture
communities	I-Architecture
,	O
reflecting	O
the	O
power	O
of	O
data	O
capitalism	O
on	O
users	O
today	O
:	O
</s>
<s>
Increasingly	O
,	O
tracking	O
and	O
surveillance	O
technology	O
is	O
profiling	B-Algorithm
users	O
and	O
learning	O
their	O
preferences	O
,	O
users	O
become	O
more	O
comfortable	O
with	O
their	O
devices	O
and	O
a	O
self-fulfilling	O
prophecy	O
continues	O
.	O
</s>
<s>
The	O
FTC	O
has	O
made	O
efforts	O
to	O
prevent	O
invasive	O
web	B-Application
tracking	I-Application
,	O
tracking	O
in	O
physical	O
space	O
,	O
malware	O
,	O
insecure	O
and	O
poorly	O
designed	O
services	O
,	O
and	O
the	O
use	O
of	O
deception	O
to	O
engage	O
in	O
surveillance	O
.	O
</s>
<s>
For	O
instance	O
,	O
in	O
the	O
realm	O
of	O
invasive	O
web	B-Application
tracking	I-Application
,	O
the	O
FTC	O
has	O
brought	O
lawsuits	O
against	O
companies	O
who	O
engage	O
in	O
'	O
history	O
sniffing'––a	O
technique	O
that	O
enables	O
companies	O
to	O
ascertain	O
which	O
links	O
a	O
user	O
clicked	O
on	O
based	O
on	O
the	O
color	O
of	O
the	O
link	O
.	O
</s>
<s>
In	O
addition	O
,	O
audio	B-Application
beacon	I-Application
technology	O
,	O
used	O
by	O
an	O
application	O
called	O
Silverpush	B-Application
,	O
could	O
violate	O
the	O
FTC	O
's	O
policies	O
because	O
users	O
were	O
not	O
made	O
aware	O
as	O
to	O
when	O
the	O
ultrasonic	O
signals	O
were	O
being	O
recorded	O
.	O
</s>
<s>
Another	O
scholar	O
believes	O
that	O
the	O
convergence	O
between	O
lived	O
experience	O
and	O
online	O
technology	O
is	O
creating	O
a	O
term	O
called	O
Mixed	B-General_Concept
reality	I-General_Concept
,	O
in	O
which	O
people	O
and	O
things	O
are	O
replaced	O
with	O
virtual	O
experiences	O
.	O
</s>
<s>
Mixed	B-General_Concept
Reality	I-General_Concept
technologies	O
can	O
pose	O
legal	O
challenges	O
in	O
that	O
laws	O
which	O
govern	O
the	O
online	O
world	O
will	O
also	O
extend	O
to	O
the	O
real	O
world	O
.	O
</s>
<s>
In	O
addition	O
,	O
data	O
tagging	O
–	O
–	O
often	O
through	O
GPS	O
,	O
location-based	B-Application
services	I-Application
,	O
or	O
even	O
near-field	O
communication	O
(	O
NFC	O
)	O
–	O
–	O
is	O
the	O
new	O
technology	O
at	O
the	O
heart	O
of	O
mixed	B-General_Concept
reality	I-General_Concept
,	O
since	O
people	O
's	O
data	O
is	O
determined	O
in	O
part	O
by	O
their	O
location	O
.	O
</s>
<s>
In	O
turn	O
,	O
mixed	B-General_Concept
reality	I-General_Concept
's	O
amalgamation	O
with	O
daily	O
tasks	O
suggest	O
that	O
it	O
will	O
be	O
implicated	O
in	O
numerous	O
legal	O
issues	O
ranging	O
from	O
copyright	O
law	O
to	O
intellectual	O
property	O
law	O
.	O
</s>
<s>
The	O
usage	O
of	O
surreptitious	O
methods	O
,	O
in	O
which	O
the	O
user	O
is	O
unaware	O
of	O
the	O
extent	O
to	O
which	O
he	O
or	O
she	O
is	O
being	O
tracked	O
,	O
brings	O
tracking	O
mechanisms	O
–	O
–	O
such	O
as	O
cookies	B-Application
,	O
flash	O
cookies	B-Application
,	O
and	O
web	B-Protocol
beacons	I-Protocol
–	O
–	O
into	O
the	O
ethical	O
realm	O
as	O
well	O
since	O
users	O
are	O
not	O
being	O
informed	O
of	O
this	O
tracking	O
perhaps	O
as	O
often	O
as	O
they	O
should	O
.	O
</s>
