<s>
Xenon	B-Protocol
is	O
software	O
to	O
perform	O
covert	O
Internet	B-Application
searches	I-Application
and	O
surveillance	O
,	O
presently	O
in	O
use	O
by	O
taxing	O
authorities	O
in	O
at	O
least	O
six	O
nations	O
to	O
investigate	O
the	O
possibilities	O
of	O
tax	O
evasion	O
by	O
various	O
revenue	O
producing	O
web	O
sites	O
(	O
online	O
shops	O
,	O
gambling	O
sites	O
,	O
or	O
pornography	O
sites	O
)	O
and	O
clients	O
selling	O
goods	O
on	O
on-line	O
auction	O
sites	O
.	O
</s>
<s>
The	O
software	O
uses	O
time-controlled	O
web	B-Application
spiders	I-Application
to	O
avoid	O
detection	O
,	O
and	O
likely	O
countermeasures	O
,	O
by	O
the	O
webmasters	O
of	O
the	O
targeted	O
site	O
.	O
</s>
<s>
Use	O
of	O
Xenon	B-Protocol
was	O
begun	O
in	O
the	O
Netherlands	O
in	O
2004	O
,	O
by	O
the	O
Dutch	O
tax	O
authority	O
Belastingdienst	O
.	O
</s>
<s>
Sweden	O
's	O
tax	O
authority	O
began	O
using	O
Xenon	B-Protocol
in	O
2007	O
.	O
</s>
<s>
Swedish	O
privacy	O
advocate	O
and	O
IT	O
expert	O
Par	O
Strom	O
,	O
while	O
stating	O
in	O
2007	O
that	O
the	O
anticipated	O
use	O
of	O
Xenon	B-Protocol
by	O
the	O
Swedish	O
tax	O
authority	O
Skatteverket	O
would	O
be	O
legal	O
,	O
has	O
also	O
stated	O
that	O
such	O
use	O
would	O
pose	O
dangers	O
to	O
citizen	O
privacy	O
rights	O
—	O
as	O
did	O
the	O
current	O
use	O
at	O
the	O
time	O
of	O
similar	O
spidering	B-Application
software	O
developed	O
internally	O
by	O
the	O
Swedish	O
government	O
.	O
</s>
