<s>
A	O
metasearch	B-Application
engine	I-Application
(	O
or	O
search	B-Application
aggregator	I-Application
)	O
is	O
an	O
online	O
information	B-Library
retrieval	I-Library
tool	O
that	O
uses	O
the	O
data	O
of	O
a	O
web	B-Application
search	I-Application
engine	I-Application
to	O
produce	O
its	O
own	O
results	O
.	O
</s>
<s>
Metasearch	B-Application
engines	I-Application
take	O
input	O
from	O
a	O
user	O
and	O
immediately	O
query	B-Library
search	B-Application
engines	I-Application
for	O
results	O
.	O
</s>
<s>
The	O
process	O
of	O
fusion	O
aims	O
to	O
improve	O
the	O
engineering	O
of	O
a	O
metasearch	B-Application
engine	I-Application
.	O
</s>
<s>
Examples	O
of	O
metasearch	B-Application
engines	I-Application
include	O
Skyscanner	O
and	O
Kayak.com,	O
which	O
aggregate	O
search	B-Application
results	I-Application
of	O
online	O
travel	O
agencies	O
and	O
provider	O
websites	O
and	O
Searx	B-Application
,	O
a	O
free	B-Application
and	O
open-source	B-Application
search	I-Application
engine	I-Application
which	O
aggregates	O
results	O
from	O
internet	B-Application
search	I-Application
engines	I-Application
.	O
</s>
<s>
He	O
developed	O
SearchSavvy	O
,	O
which	O
let	O
users	O
search	O
up	O
to	O
20	O
different	O
search	B-Application
engines	I-Application
and	O
directories	O
at	O
once	O
.	O
</s>
<s>
Although	O
fast	O
,	O
the	O
search	B-Application
engine	I-Application
was	O
restricted	O
to	O
simple	O
searches	O
and	O
thus	O
was	O
n't	O
reliable	O
.	O
</s>
<s>
University	O
of	O
Washington	O
student	O
Eric	O
Selberg	O
released	O
a	O
more	O
"	O
updated	O
"	O
version	O
called	O
MetaCrawler	B-Application
.	O
</s>
<s>
This	O
search	B-Application
engine	I-Application
improved	O
on	O
SearchSavvy	O
's	O
accuracy	O
by	O
adding	O
its	O
own	O
search	O
syntax	O
behind	O
the	O
scenes	O
,	O
and	O
matching	O
the	O
syntax	O
to	O
that	O
of	O
the	O
search	B-Application
engines	I-Application
it	O
was	O
probing	O
.	O
</s>
<s>
Metacrawler	B-Application
reduced	O
the	O
amount	O
of	O
search	B-Application
engines	I-Application
queried	O
to	O
6	O
,	O
but	O
although	O
it	O
produced	O
more	O
accurate	O
results	O
,	O
it	O
still	O
was	O
n't	O
considered	O
as	O
accurate	O
as	O
searching	O
a	O
query	B-Library
in	O
an	O
individual	O
engine	O
.	O
</s>
<s>
On	O
May	O
20	O
,	O
1996	O
,	O
HotBot	B-Application
,	O
then	O
owned	O
by	O
Wired	O
,	O
was	O
a	O
search	B-Application
engine	I-Application
with	O
search	B-Application
results	I-Application
coming	O
from	O
the	O
Inktomi	B-Application
and	O
Direct	O
Hit	O
databases	O
.	O
</s>
<s>
It	O
was	O
known	O
for	O
its	O
fast	O
results	O
and	O
as	O
a	O
search	B-Application
engine	I-Application
with	O
the	O
ability	O
to	O
search	O
within	O
search	B-Application
results	I-Application
.	O
</s>
<s>
Upon	O
being	O
bought	O
by	O
Lycos	B-Application
in	O
1998	O
,	O
development	O
for	O
the	O
search	B-Application
engine	I-Application
staggered	O
and	O
its	O
market	O
share	O
fell	O
drastically	O
.	O
</s>
<s>
After	O
going	O
through	O
a	O
few	O
alterations	O
,	O
HotBot	B-Application
was	O
redesigned	O
into	O
a	O
simplified	O
search	O
interface	O
,	O
with	O
its	O
features	O
being	O
incorporated	O
into	O
Lycos	B-Application
 '	O
website	O
redesign	O
.	O
</s>
<s>
A	O
metasearch	B-Application
engine	I-Application
called	O
Anvish	O
was	O
developed	O
by	O
Bo	O
Shu	O
and	O
Subhash	O
Kak	O
in	O
1999	O
;	O
the	O
search	B-Application
results	I-Application
were	O
sorted	O
using	O
instantaneously	B-Algorithm
trained	I-Algorithm
neural	I-Algorithm
networks	I-Algorithm
.	O
</s>
<s>
This	O
was	O
later	O
incorporated	O
into	O
another	O
metasearch	B-Application
engine	I-Application
called	O
Solosearch	B-Application
.	O
</s>
<s>
In	O
August	O
2000	O
,	O
India	O
got	O
its	O
first	O
meta	B-Application
search	I-Application
engine	I-Application
when	O
HumHaiIndia.com	O
was	O
launched	O
.	O
</s>
<s>
Ixquick	O
is	O
a	O
search	B-Application
engine	I-Application
known	O
for	O
its	O
privacy	O
policy	O
statement	O
.	O
</s>
<s>
In	O
June	O
2006	O
,	O
Ixquick	O
began	O
to	O
delete	O
private	O
details	O
of	O
its	O
users	O
following	O
the	O
same	O
process	O
with	O
Scroogle	B-Application
.	O
</s>
<s>
The	O
more	O
stars	O
in	O
a	O
result	O
,	O
the	O
more	O
search	B-Application
engines	I-Application
agreed	O
on	O
the	O
result	O
.	O
</s>
<s>
In	O
April	O
2005	O
,	O
Dogpile	B-Application
,	O
then	O
owned	O
and	O
operated	O
by	O
InfoSpace	O
,	O
Inc.	O
,	O
collaborated	O
with	O
researchers	O
from	O
the	O
University	O
of	O
Pittsburgh	O
and	O
Pennsylvania	O
State	O
University	O
to	O
measure	O
the	O
overlap	O
and	O
ranking	O
differences	O
of	O
leading	O
Web	B-Application
search	I-Application
engines	I-Application
in	O
order	O
to	O
gauge	O
the	O
benefits	O
of	O
using	O
a	O
metasearch	B-Application
engine	I-Application
to	O
search	B-Application
the	I-Application
web	I-Application
.	O
</s>
<s>
Results	O
found	O
that	O
from	O
10,316	O
random	O
user-defined	O
queries	B-Library
from	O
Google	B-Application
,	O
Yahoo	O
!,	O
and	O
Ask	B-Application
Jeeves	I-Application
,	O
only	O
3.2	O
%	O
of	O
first	O
page	O
search	B-Application
results	I-Application
were	O
the	O
same	O
across	O
those	O
search	B-Application
engines	I-Application
for	O
a	O
given	O
query	B-Library
.	O
</s>
<s>
Another	O
study	O
later	O
that	O
year	O
using	O
12,570	O
random	O
user-defined	O
queries	B-Library
from	O
Google	B-Application
,	O
Yahoo	O
!,	O
MSN	B-Application
Search	I-Application
,	O
and	O
Ask	B-Application
Jeeves	I-Application
found	O
that	O
only	O
1.1	O
%	O
of	O
first	O
page	O
search	B-Application
results	I-Application
were	O
the	O
same	O
across	O
those	O
search	B-Application
engines	I-Application
for	O
a	O
given	O
query	B-Library
.	O
</s>
<s>
By	O
sending	O
multiple	O
queries	B-Library
to	O
several	O
other	O
search	B-Application
engines	I-Application
this	O
extends	O
the	O
coverage	B-General_Concept
data	I-General_Concept
of	O
the	O
topic	O
and	O
allows	O
more	O
information	O
to	O
be	O
found	O
.	O
</s>
<s>
They	O
use	O
the	O
indexes	O
built	O
by	O
other	O
search	B-Application
engines	I-Application
,	O
aggregating	O
and	O
often	O
post-processing	O
results	O
in	O
unique	O
ways	O
.	O
</s>
<s>
A	O
metasearch	B-Application
engine	I-Application
has	O
an	O
advantage	O
over	O
a	O
single	O
search	B-Application
engine	I-Application
because	O
more	O
results	O
can	O
be	O
retrieved	B-Application
with	O
the	O
same	O
amount	O
of	O
exertion	O
.	O
</s>
<s>
Metasearching	B-Application
is	O
also	O
a	O
useful	O
approach	O
if	O
the	O
purpose	O
of	O
the	O
user	O
's	O
search	O
is	O
to	O
get	O
an	O
overview	O
of	O
the	O
topic	O
or	O
to	O
get	O
quick	O
answers	O
.	O
</s>
<s>
Instead	O
of	O
having	O
to	O
go	O
through	O
multiple	O
search	B-Application
engines	I-Application
like	O
Yahoo	B-Application
!	I-Application
</s>
<s>
or	O
Google	B-Application
and	O
comparing	O
results	O
,	O
metasearch	B-Application
engines	I-Application
are	O
able	O
to	O
quickly	O
compile	O
and	O
combine	O
results	O
.	O
</s>
<s>
They	O
can	O
do	O
it	O
either	O
by	O
listing	O
results	O
from	O
each	O
engine	O
queried	O
with	O
no	O
additional	O
post-processing	O
(	O
Dogpile	B-Application
)	O
or	O
by	O
analyzing	O
the	O
results	O
and	O
ranking	O
them	O
by	O
their	O
own	O
rules	O
(	O
IxQuick	O
,	O
Metacrawler	B-Application
,	O
and	O
Vivismo	O
)	O
.	O
</s>
<s>
A	O
metasearch	B-Application
engine	I-Application
can	O
also	O
hide	O
the	O
searcher	O
's	O
IP	O
address	O
from	O
the	O
search	B-Application
engines	I-Application
queried	O
thus	O
providing	O
privacy	O
to	O
the	O
search	O
.	O
</s>
<s>
Metasearch	B-Application
engines	I-Application
are	O
not	O
capable	O
of	O
parsing	B-Language
query	B-Library
forms	O
or	O
able	O
to	O
fully	O
translate	O
query	B-Library
syntax	O
.	O
</s>
<s>
The	O
number	O
of	O
hyperlinks	O
generated	O
by	O
metasearch	B-Application
engines	I-Application
are	O
limited	O
,	O
and	O
therefore	O
do	O
not	O
provide	O
the	O
user	O
with	O
the	O
complete	O
results	O
of	O
a	O
query	B-Library
.	O
</s>
<s>
The	O
majority	O
of	O
metasearch	B-Application
engines	I-Application
do	O
not	O
provide	O
over	O
ten	O
linked	O
files	O
from	O
a	O
single	O
search	B-Application
engine	I-Application
,	O
and	O
generally	O
do	O
not	O
interact	O
with	O
larger	O
search	B-Application
engines	I-Application
for	O
results	O
.	O
</s>
<s>
Metasearching	B-Application
also	O
gives	O
the	O
illusion	O
that	O
there	O
is	O
more	O
coverage	O
of	O
the	O
topic	O
queried	O
,	O
particularly	O
if	O
the	O
user	O
is	O
searching	O
for	O
popular	O
or	O
commonplace	O
information	O
.	O
</s>
<s>
It	O
is	O
also	O
harder	O
for	O
users	O
to	O
search	O
with	O
advanced	O
search	O
syntax	O
to	O
be	O
sent	O
with	O
the	O
query	B-Library
,	O
so	O
results	O
may	O
not	O
be	O
as	O
precise	O
as	O
when	O
a	O
user	O
is	O
using	O
an	O
advanced	O
search	O
interface	O
at	O
a	O
specific	O
engine	O
.	O
</s>
<s>
This	O
results	O
in	O
many	O
metasearch	B-Application
engines	I-Application
using	O
simple	O
searching	O
.	O
</s>
<s>
A	O
metasearch	B-Application
engine	I-Application
accepts	O
a	O
single	O
search	O
request	O
from	O
the	O
user	O
.	O
</s>
<s>
This	O
search	O
request	O
is	O
then	O
passed	O
on	O
to	O
another	O
search	B-Application
engine	I-Application
's	O
database	O
.	O
</s>
<s>
A	O
metasearch	B-Application
engine	I-Application
does	O
not	O
create	O
a	O
database	O
of	O
web	O
pages	O
but	O
generates	O
a	O
Federated	B-General_Concept
database	I-General_Concept
system	I-General_Concept
of	O
data	B-General_Concept
integration	I-General_Concept
from	O
multiple	O
sources	O
.	O
</s>
<s>
Since	O
every	O
search	B-Application
engine	I-Application
is	O
unique	O
and	O
has	O
different	O
algorithms	O
for	O
generating	O
ranked	O
data	O
,	O
duplicates	O
will	O
therefore	O
also	O
be	O
generated	O
.	O
</s>
<s>
To	O
remove	O
duplicates	O
,	O
a	O
metasearch	B-Application
engine	I-Application
processes	O
this	O
data	O
and	O
applies	O
its	O
own	O
algorithm	O
.	O
</s>
<s>
When	O
a	O
metasearch	B-Application
engine	I-Application
contacts	O
other	O
search	B-Application
engines	I-Application
,	O
these	O
search	B-Application
engines	I-Application
will	O
respond	O
in	O
three	O
ways	O
:	O
</s>
<s>
They	O
will	O
both	O
cooperate	O
and	O
provide	O
complete	O
access	O
to	O
the	O
interface	O
for	O
the	O
metasearch	B-Application
engine	I-Application
,	O
including	O
private	O
access	O
to	O
the	O
index	O
database	O
,	O
and	O
will	O
inform	O
the	O
metasearch	B-Application
engine	I-Application
of	O
any	O
changes	O
made	O
upon	O
the	O
index	O
database	O
;	O
</s>
<s>
Search	B-Application
engines	I-Application
can	O
behave	O
in	O
a	O
non-cooperative	O
manner	O
whereby	O
they	O
will	O
not	O
deny	O
or	O
provide	O
any	O
access	O
to	O
interfaces	O
;	O
</s>
<s>
The	O
search	B-Application
engine	I-Application
can	O
be	O
completely	O
hostile	O
and	O
refuse	O
the	O
metasearch	B-Application
engine	I-Application
total	O
access	O
to	O
their	O
database	O
and	O
in	O
serious	O
circumstances	O
,	O
by	O
seeking	O
legal	O
methods	O
.	O
</s>
<s>
Web	O
pages	O
that	O
are	O
highly	O
ranked	O
on	O
many	O
search	B-Application
engines	I-Application
are	O
likely	O
to	O
be	O
more	O
relevant	O
in	O
providing	O
useful	O
information	O
.	O
</s>
<s>
However	O
,	O
all	O
search	B-Application
engines	I-Application
have	O
different	O
ranking	O
scores	O
for	O
each	O
website	O
and	O
most	O
of	O
the	O
time	O
these	O
scores	O
are	O
not	O
the	O
same	O
.	O
</s>
<s>
This	O
is	O
because	O
search	B-Application
engines	I-Application
prioritise	O
different	O
criteria	O
and	O
methods	O
for	O
scoring	O
,	O
hence	O
a	O
website	O
might	O
appear	O
highly	O
ranked	O
on	O
one	O
search	B-Application
engine	I-Application
and	O
lowly	O
ranked	O
on	O
another	O
.	O
</s>
<s>
This	O
is	O
a	O
problem	O
because	O
Metasearch	B-Application
engines	I-Application
rely	O
heavily	O
on	O
the	O
consistency	O
of	O
this	O
data	O
to	O
generate	O
reliable	O
accounts	O
.	O
</s>
<s>
A	O
metasearch	B-Application
engine	I-Application
uses	O
the	O
process	O
of	O
Fusion	O
to	O
filter	O
data	O
for	O
more	O
efficient	O
results	O
.	O
</s>
<s>
Collection	O
Fusion	O
:	O
also	O
known	O
as	O
distributed	O
retrieval	O
,	O
deals	O
specifically	O
with	O
search	B-Application
engines	I-Application
that	O
index	O
unrelated	O
data	O
.	O
</s>
<s>
To	O
determine	O
how	O
valuable	O
these	O
sources	O
are	O
,	O
Collection	O
Fusion	O
looks	O
at	O
the	O
content	O
and	O
then	O
ranks	O
the	O
data	O
on	O
how	O
likely	O
it	O
is	O
to	O
provide	O
relevant	O
information	O
in	O
relation	O
to	O
the	O
query	B-Library
.	O
</s>
<s>
Data	O
Fusion	O
:	O
deals	O
with	O
information	O
retrieved	B-Application
from	O
search	B-Application
engines	I-Application
that	O
indexes	O
common	O
data	O
sets	O
.	O
</s>
<s>
Data	O
with	O
high	O
scores	O
indicate	O
a	O
high	O
level	O
of	O
relevancy	O
to	O
a	O
particular	O
query	B-Library
and	O
are	O
therefore	O
selected	O
.	O
</s>
<s>
This	O
is	O
because	O
search	B-Application
engines	I-Application
adopt	O
different	O
policies	O
of	O
algorithms	O
resulting	O
in	O
the	O
score	O
produced	O
being	O
incomparable	O
.	O
</s>
<s>
Spamdexing	O
is	O
the	O
deliberate	O
manipulation	O
of	O
search	B-Application
engine	I-Application
indexes	O
.	O
</s>
<s>
Spamdexing	O
can	O
be	O
very	O
distressing	O
for	O
users	O
and	O
problematic	O
for	O
search	B-Application
engines	I-Application
because	O
the	O
return	O
contents	O
of	O
searches	O
have	O
poor	O
precision	O
.	O
</s>
<s>
This	O
will	O
eventually	O
result	O
in	O
the	O
search	B-Application
engine	I-Application
becoming	O
unreliable	O
and	O
not	O
dependable	O
for	O
the	O
user	O
.	O
</s>
<s>
To	O
tackle	O
Spamdexing	O
,	O
search	B-Application
robot	I-Application
algorithms	O
are	O
made	O
more	O
complex	O
and	O
are	O
changed	O
almost	O
every	O
day	O
to	O
eliminate	O
the	O
problem	O
.	O
</s>
<s>
It	O
is	O
a	O
major	O
problem	O
for	O
metasearch	B-Application
engines	I-Application
because	O
it	O
tampers	O
with	O
the	O
Web	B-Application
crawler	I-Application
's	O
indexing	O
criteria	O
,	O
which	O
are	O
heavily	O
relied	O
upon	O
to	O
format	O
ranking	O
lists	O
.	O
</s>
<s>
Spamdexing	O
manipulates	O
the	O
natural	O
ranking	O
system	O
of	O
a	O
search	B-Application
engine	I-Application
,	O
and	O
places	O
websites	O
higher	O
on	O
the	O
ranking	O
list	O
than	O
they	O
would	O
naturally	O
be	O
placed	O
.	O
</s>
<s>
Content	O
spam	O
are	O
the	O
techniques	O
that	O
alter	O
the	O
logical	O
view	O
that	O
a	O
search	B-Application
engine	I-Application
has	O
over	O
the	O
page	O
's	O
contents	O
.	O
</s>
<s>
This	O
is	O
a	O
SEO	O
technique	O
in	O
which	O
different	O
materials	O
and	O
information	O
are	O
sent	O
to	O
the	O
web	B-Application
crawler	I-Application
and	O
to	O
the	O
web	B-Application
browser	I-Application
.	O
</s>
<s>
It	O
is	O
commonly	O
used	O
as	O
a	O
spamdexing	O
technique	O
because	O
it	O
can	O
trick	O
search	B-Application
engines	I-Application
into	O
either	O
visiting	O
a	O
site	O
that	O
is	O
substantially	O
different	O
from	O
the	O
search	B-Application
engine	I-Application
description	O
or	O
giving	O
a	O
certain	O
site	O
a	O
higher	O
ranking	O
.	O
</s>
