<s>
A	O
wordfilter	B-Application
(	O
sometimes	O
referred	O
to	O
as	O
just	O
"	O
filter	O
"	O
or	O
"	O
censor	O
"	O
)	O
is	O
a	O
script	O
typically	O
used	O
on	O
Internet	B-Application
forums	I-Application
or	O
chat	O
rooms	O
that	O
automatically	O
scans	O
users	O
 '	O
posts	O
or	O
comments	O
as	O
they	O
are	O
submitted	O
and	O
automatically	O
changes	O
or	O
censors	O
particular	O
words	O
or	O
phrases	O
.	O
</s>
<s>
The	O
most	O
basic	O
wordfilters	B-Application
search	O
only	O
for	O
specific	O
strings	O
of	O
letters	O
,	O
and	O
remove	O
or	O
overwrite	O
them	O
regardless	O
of	O
their	O
context	O
.	O
</s>
<s>
More	O
advanced	O
wordfilters	B-Application
make	O
some	O
exceptions	O
for	O
context	O
(	O
such	O
as	O
filtering	O
"	O
butt	O
"	O
but	O
not	O
"	O
butter	O
"	O
)	O
,	O
and	O
the	O
most	O
advanced	O
wordfilters	B-Application
may	O
use	O
regular	B-Language
expressions	I-Language
.	O
</s>
<s>
Wordfilters	B-Application
can	O
serve	O
any	O
of	O
a	O
number	O
of	O
functions	O
.	O
</s>
<s>
A	O
swear	B-Application
filter	I-Application
,	O
also	O
known	O
as	O
a	O
profanity	B-Application
filter	I-Application
or	O
language	O
filter	O
is	O
a	O
software	O
subsystem	O
which	O
modifies	O
text	O
to	O
remove	O
words	O
deemed	O
offensive	O
by	O
the	O
administrator	O
or	O
community	O
of	O
an	O
online	B-Application
forum	I-Application
.	O
</s>
<s>
Swear	B-Application
filters	I-Application
are	O
common	O
in	O
custom-programmed	O
chat	O
rooms	O
and	O
online	B-Application
video	I-Application
games	I-Application
,	O
primarily	O
MMORPGs	B-Protocol
.	O
</s>
<s>
This	O
is	O
not	O
to	O
be	O
confused	O
with	O
content	B-Protocol
filtering	I-Protocol
,	O
which	O
is	O
usually	O
built	O
into	O
internet	O
browsing	O
programs	O
by	O
third-party	O
developers	O
to	O
filter	O
or	O
block	O
specific	O
websites	O
or	O
types	O
of	O
websites	O
.	O
</s>
<s>
Swear	B-Application
filters	I-Application
are	O
usually	O
created	O
or	O
implemented	O
by	O
the	O
developers	O
of	O
the	O
Internet	O
service	O
.	O
</s>
<s>
Most	O
commonly	O
,	O
wordfilters	B-Application
are	O
used	O
to	O
censor	O
language	O
considered	O
inappropriate	O
by	O
the	O
operators	O
of	O
the	O
forum	O
or	O
chat	O
room	O
.	O
</s>
<s>
This	O
may	O
also	O
help	O
the	O
message	B-Application
board	I-Application
avoid	O
content-control	B-Protocol
software	I-Protocol
installed	O
on	O
users	O
 '	O
computers	O
or	O
networks	O
,	O
since	O
such	O
software	O
often	O
blocks	O
access	O
to	O
Web	O
pages	O
that	O
contain	O
vulgar	O
language	O
.	O
</s>
<s>
Filtered	O
phrases	O
may	O
be	O
permanently	O
replaced	O
as	O
it	O
is	O
saved	O
(	O
example	O
:	O
phpBB	B-Application
1.x	O
)	O
,	O
or	O
the	O
original	O
phrase	O
may	O
be	O
saved	O
but	O
displayed	O
as	O
the	O
censored	O
text	O
.	O
</s>
<s>
In	O
some	O
software	O
users	O
can	O
view	O
the	O
text	O
behind	O
the	O
wordfilter	B-Application
by	O
quoting	O
the	O
post	O
.	O
</s>
<s>
Swear	B-Application
filters	I-Application
typically	O
take	O
advantage	O
of	O
string	O
replacement	O
functions	O
built	O
into	O
the	O
programming	O
language	O
used	O
to	O
create	O
the	O
program	O
,	O
to	O
swap	O
out	O
a	O
list	O
of	O
inappropriate	O
words	O
and	O
phrases	O
with	O
a	O
variety	O
of	O
alternatives	O
.	O
</s>
<s>
Some	O
swear	B-Application
filters	I-Application
do	O
a	O
simple	O
search	O
for	O
a	O
string	O
.	O
</s>
<s>
Administrators	O
may	O
configure	O
the	O
wordfilter	B-Application
to	O
replace	O
the	O
annoying	O
cliché	O
with	O
a	O
more	O
embarrassing	O
phrase	O
,	O
or	O
remove	O
it	O
altogether	O
.	O
</s>
<s>
Internet	B-Application
forums	I-Application
are	O
sometimes	O
attacked	O
by	O
vandals	O
who	O
try	O
to	O
fill	O
the	O
forum	O
with	O
repeated	O
nonsense	O
messages	O
,	O
or	O
by	O
spammers	O
who	O
try	O
to	O
insert	O
links	O
to	O
their	O
commercial	O
web	O
sites	O
.	O
</s>
<s>
The	O
site	O
's	O
wordfilter	B-Application
may	O
be	O
configured	O
to	O
remove	O
the	O
nonsense	O
text	O
used	O
by	O
the	O
vandals	O
,	O
or	O
to	O
remove	O
all	O
links	O
to	O
particular	O
websites	O
from	O
posts	O
.	O
</s>
<s>
Lameness	B-Application
filters	I-Application
are	O
text-based	O
wordfilters	B-Application
used	O
by	O
Slash-based	O
websites	O
(	O
i.e.	O
</s>
<s>
Since	O
wordfilters	B-Application
are	O
automated	O
and	O
look	O
only	O
for	O
particular	O
sequences	O
of	O
characters	O
,	O
users	O
aware	O
of	O
the	O
filters	O
will	O
sometimes	O
try	O
to	O
circumvent	O
them	O
by	O
changing	O
their	O
lettering	O
just	O
enough	O
to	O
avoid	O
the	O
filters	O
.	O
</s>
<s>
Some	O
administrators	O
respond	O
by	O
revising	O
the	O
wordfilters	B-Application
to	O
catch	O
common	O
substitutions	O
;	O
others	O
may	O
make	O
filter	O
evasion	O
a	O
punishable	O
offense	O
of	O
its	O
own	O
.	O
</s>
<s>
A	O
simple	O
example	O
of	O
evading	O
a	O
wordfilter	B-Application
would	O
be	O
entering	O
symbols	O
between	O
letters	O
or	O
using	O
leet	B-Language
.	O
</s>
<s>
More	O
advanced	O
techniques	O
of	O
wordfilter	B-Application
evasion	O
include	O
the	O
use	O
of	O
images	O
,	O
using	O
hidden	O
tags	O
,	O
or	O
Cyrillic	O
characters	O
(	O
i.e.	O
</s>
<s>
a	O
homograph	B-General_Concept
spoofing	I-General_Concept
attack	I-General_Concept
)	O
.	O
</s>
<s>
By	O
placing	O
this	O
halfway	O
in	O
a	O
word	O
,	O
the	O
word	O
gets	O
broken	O
up	O
and	O
will	O
in	O
some	O
cases	O
not	O
be	O
recognised	O
by	O
the	O
wordfilter	B-Application
.	O
</s>
<s>
Some	O
more	O
advanced	O
filters	O
,	O
such	O
as	O
those	O
in	O
the	O
online	B-Application
game	I-Application
RuneScape	B-Protocol
,	O
can	O
detect	O
bypassing	O
.	O
</s>
<s>
However	O
,	O
the	O
downside	O
of	O
sensitive	O
wordfilters	B-Application
is	O
that	O
legitimate	O
phrases	O
get	O
filtered	O
out	O
as	O
well	O
.	O
</s>
<s>
Wordfilters	B-Application
are	O
coded	O
into	O
the	O
Internet	B-Application
forums	I-Application
or	O
chat	O
rooms	O
,	O
and	O
operate	O
only	O
on	O
material	O
submitted	O
to	O
the	O
forum	O
or	O
chat	O
room	O
in	O
question	O
.	O
</s>
<s>
This	O
distinguishes	O
wordfilters	B-Application
from	O
content-control	B-Protocol
software	I-Protocol
,	O
which	O
is	O
typically	O
installed	O
on	O
an	O
end	O
user	O
's	O
PC	O
or	O
computer	O
network	O
,	O
and	O
which	O
can	O
filter	O
all	O
Internet	O
content	O
sent	O
to	O
or	O
from	O
the	O
PC	O
or	O
network	O
in	O
question	O
.	O
</s>
<s>
Since	O
wordfilters	B-Application
alter	O
users	O
 '	O
words	O
without	O
their	O
consent	O
,	O
some	O
users	O
still	O
consider	O
them	O
to	O
be	O
censorship	O
,	O
while	O
others	O
consider	O
them	O
an	O
acceptable	O
part	O
of	O
a	O
forum	O
operator	O
's	O
right	O
to	O
control	O
the	O
contents	O
of	O
the	O
forum	O
.	O
</s>
<s>
A	O
common	O
quirk	O
with	O
wordfilters	B-Application
,	O
often	O
considered	O
either	O
comical	O
or	O
aggravating	O
by	O
users	O
,	O
is	O
that	O
they	O
often	O
affect	O
words	O
that	O
are	O
not	O
intended	O
to	O
be	O
filtered	O
.	O
</s>
<s>
One	O
example	O
of	O
this	O
is	O
found	O
on	O
the	O
Myst	B-Application
forum	O
Mystcommunity	O
.	O
</s>
<s>
In	O
the	O
early	O
years	O
of	O
the	O
internet	O
,	O
the	O
British	O
place	O
name	O
Penistone	O
was	O
often	O
filtered	O
out	O
from	O
spam	O
and	O
swear	B-Application
filters	I-Application
.	O
</s>
<s>
Many	O
games	O
,	O
such	O
as	O
World	B-Protocol
of	I-Protocol
Warcraft	I-Protocol
,	O
and	O
more	O
recently	O
,	O
Habbo	B-Application
Hotel	I-Application
and	O
RuneScape	B-Protocol
allow	O
users	O
to	O
turn	O
the	O
filters	O
off	O
.	O
</s>
<s>
Other	O
games	O
,	O
especially	O
free	O
Massively	B-Application
multiplayer	I-Application
online	I-Application
games	I-Application
,	O
such	O
as	O
Knight	B-Protocol
Online	I-Protocol
do	O
not	O
have	O
such	O
an	O
option	O
.	O
</s>
<s>
Other	O
games	O
such	O
as	O
Medal	O
of	O
Honor	O
and	O
Call	B-Application
of	I-Application
Duty	I-Application
(	O
except	O
Call	B-Application
of	I-Application
Duty	I-Application
:	I-Application
World	I-Application
at	I-Application
War	I-Application
,	O
Call	B-Application
of	I-Application
Duty	I-Application
:	I-Application
Black	I-Application
Ops	I-Application
,	O
Call	B-Application
of	I-Application
Duty	I-Application
:	I-Application
Black	I-Application
Ops	I-Application
2	I-Application
,	O
and	O
Call	B-Application
of	I-Application
Duty	I-Application
:	I-Application
Black	I-Application
Ops	I-Application
3	I-Application
)	O
do	O
not	O
give	O
users	O
the	O
option	O
to	O
turn	O
off	O
scripted	O
foul	O
language	O
,	O
while	O
Gears	B-Application
of	I-Application
War	I-Application
does	O
.	O
</s>
<s>
In	O
addition	O
to	O
games	O
,	O
profanity	B-Application
filters	I-Application
can	O
be	O
used	O
to	O
moderate	O
user	O
generated	O
content	O
in	O
forums	O
,	O
blogs	O
,	O
social	O
media	O
apps	O
,	O
kid	O
's	O
websites	O
,	O
and	O
product	O
reviews	O
.	O
</s>
<s>
There	O
are	O
many	O
profanity	B-Application
filter	I-Application
APIs	O
like	O
that	O
help	O
in	O
replacing	O
the	O
swear	O
words	O
with	O
other	O
characters	O
(	O
i.e.	O
</s>
<s>
These	O
profanity	B-Application
filters	I-Application
APIs	O
work	O
with	O
profanity	B-Protocol
search	O
and	O
replace	O
method	O
.	O
</s>
