<s>
A	O
selection-based	B-Application
search	I-Application
system	O
is	O
a	O
search	B-Application
engine	I-Application
system	O
in	O
which	O
the	O
user	O
invokes	O
a	O
search	O
query	O
using	O
only	O
the	O
mouse	B-Device
.	O
</s>
<s>
A	O
selection-based	B-Application
search	I-Application
system	O
allows	O
the	O
user	O
to	O
search	O
the	O
internet	O
for	O
more	O
information	O
about	O
any	O
keyword	O
or	O
phrase	O
contained	O
within	O
a	O
document	O
or	O
webpage	O
in	O
any	O
software	O
application	O
on	O
their	O
desktop	O
computer	O
using	O
the	O
mouse	B-Device
.	O
</s>
<s>
Traditional	O
browser-based	O
search	O
systems	O
require	O
the	O
user	O
to	O
launch	O
a	O
web	B-Application
browser	I-Application
,	O
navigate	O
to	O
a	O
search	O
page	O
,	O
type	O
or	O
paste	O
a	O
query	O
into	O
a	O
search	O
box	O
,	O
review	O
a	O
list	O
of	O
results	O
,	O
and	O
click	O
a	O
hyperlink	O
to	O
view	O
these	O
results	O
.	O
</s>
<s>
Three	O
characteristic	O
features	O
of	O
a	O
selection-based	B-Application
search	I-Application
system	O
are	O
that	O
the	O
user	O
can	O
invoke	O
search	O
using	O
only	O
their	O
mouse	B-Device
from	O
within	O
the	O
context	O
of	O
any	O
application	O
on	O
their	O
desktop	O
(	O
for	O
example	O
Microsoft	B-Application
Office	I-Application
,	O
Adobe	B-Application
Reader	I-Application
,	O
Mozilla	B-Application
Firefox	I-Application
,	O
etc	O
.	O
</s>
<s>
In	O
its	O
simplest	O
form	O
,	O
selection-based	B-Application
search	I-Application
enables	O
users	O
to	O
launch	O
a	O
search	O
query	O
by	O
selecting	O
text	O
on	O
any	O
application	O
on	O
their	O
desktop	O
.	O
</s>
<s>
It	O
is	O
commonly	O
believed	O
that	O
selection-based	B-Application
search	I-Application
lowers	O
the	O
user	O
barrier	O
to	O
search	O
and	O
permits	O
an	O
incremental	O
number	O
of	O
searches	O
per	O
user	O
per	O
day	O
.	O
</s>
<s>
Selection-based	B-Application
search	I-Application
systems	O
also	O
operate	O
on	O
the	O
premise	O
that	O
users	O
value	O
information	O
in	O
context	O
.	O
</s>
<s>
They	O
may	O
save	O
the	O
user	O
from	O
having	O
to	O
juggle	O
multiple	O
applications	O
,	O
multiple	O
web	B-Application
browsers	I-Application
or	O
use	O
multiple	O
search	B-Application
engines	I-Application
separately	O
.	O
</s>
<s>
The	O
term	O
selection-based	B-Application
search	I-Application
is	O
frequently	O
used	O
to	O
classify	O
a	O
set	O
of	O
search	B-Application
engine	I-Application
systems	O
,	O
including	O
a	O
desktop	O
client	O
and	O
a	O
series	O
of	O
cloud	B-Architecture
computing	I-Architecture
services	O
,	O
but	O
is	O
also	O
used	O
to	O
describe	O
the	O
paradigm	O
of	O
categorizing	O
a	O
keyword	O
and	O
searching	O
multiple	O
data	O
sources	O
using	O
only	O
the	O
mouse	B-Device
.	O
</s>
<s>
The	O
National	O
Information	O
Standards	O
Organization	O
(	O
NISO	O
)	O
uses	O
the	O
terms	O
selection-based	B-Application
search	I-Application
and	O
mouse-based	B-Application
search	I-Application
interchangeably	O
to	O
describe	O
this	O
web	B-Application
search	I-Application
paradigm	O
.	O
</s>
<s>
Selection-based	B-Application
search	I-Application
systems	O
create	O
what	O
is	O
known	O
as	O
a	O
semantic	O
database	O
of	O
trained	O
terms	O
.	O
</s>
<s>
Instead	O
,	O
they	O
take	O
a	O
user	O
's	O
selected	O
keyword	O
or	O
keywords	O
,	O
pass	O
it	O
to	O
several	O
heterogeneous	O
online	O
cloud	B-Architecture
services	I-Architecture
,	O
categorize	O
the	O
keyword(s )	O
,	O
and	O
then	O
compile	O
the	O
results	O
in	O
a	O
homogeneous	O
manner	O
based	O
on	O
a	O
specific	O
algorithm	O
.	O
</s>
<s>
No	O
two	O
selection-based	B-Application
search	I-Application
systems	O
are	O
alike	O
.	O
</s>
<s>
Others	O
only	O
allow	O
the	O
user	O
to	O
search	O
their	O
desktop	O
files	O
such	O
as	O
Macintosh	B-Application
Spotlight	I-Application
,	O
or	O
to	O
search	O
a	O
popular	O
search	B-Application
engine	I-Application
such	O
as	O
Google	B-Application
or	O
Yahoo	O
!,	O
while	O
others	O
only	O
search	O
lesser-known	O
search	B-Application
engines	I-Application
,	O
newsgroups	B-Application
,	O
and	O
more	O
specialized	O
databases	O
.	O
</s>
<s>
Selection-based	B-Application
search	I-Application
systems	O
also	O
differ	O
in	O
how	O
the	O
results	O
are	O
presented	O
and	O
the	O
quality	O
of	O
semantic	O
categorization	O
which	O
is	O
used	O
.	O
</s>
<s>
Some	O
will	O
open	O
links	O
to	O
content	O
in	O
a	O
new	O
browser	B-Application
window	O
.	O
</s>
<s>
A	O
key	O
challenge	O
for	O
selection-based	B-Application
search	I-Application
is	O
that	O
a	O
long	O
or	O
nested	O
list	O
of	O
categories	O
quickly	O
becomes	O
unwieldy	O
for	O
the	O
user	O
.	O
</s>
<s>
Therefore	O
,	O
it	O
is	O
incumbent	O
upon	O
the	O
selection-based	B-Application
search	I-Application
system	O
to	O
both	O
categorize	O
the	O
user-selected	O
text	O
and	O
to	O
identify	O
those	O
online	O
services	O
which	O
most	O
naturally	O
apply	O
to	O
the	O
selected	O
text	O
.	O
</s>
<s>
For	O
example	O
,	O
when	O
the	O
user	O
selects	O
an	O
address	O
,	O
the	O
system	O
needs	O
to	O
identify	O
the	O
address	O
as	O
most	O
suitable	O
for	O
an	O
online	O
mapping	O
service	O
such	O
as	O
Google	B-Application
Maps	I-Application
.	I-Application
</s>
<s>
When	O
the	O
user	O
selects	O
the	O
name	O
of	O
a	O
company	O
,	O
the	O
system	O
needs	O
to	O
identify	O
the	O
concordant	O
stock	O
symbol	O
and	O
an	O
appropriate	O
financial	O
database	O
such	O
as	O
Yahoo	B-Application
!	I-Application
</s>
<s>
Usability	O
can	O
vary	O
widely	O
between	O
selection-based	B-Application
search	I-Application
systems	O
based	O
on	O
a	O
large	O
number	O
of	O
variables	O
.	O
</s>
<s>
Even	O
the	O
most	O
basic	O
selection-based	B-Application
search	I-Application
systems	O
will	O
allow	O
more	O
of	O
the	O
web	O
to	O
be	O
searched	O
by	O
the	O
user	O
in	O
the	O
context	O
of	O
their	O
work	O
than	O
any	O
one	O
stand-alone	O
search	B-Application
engine	I-Application
.	O
</s>
