<s>
A	O
human	B-Application
search	I-Application
engine	I-Application
was	O
a	O
search	B-Application
engine	I-Application
that	O
used	O
human	O
participation	O
to	O
filter	O
the	O
search	B-Application
results	I-Application
and	O
assist	O
users	O
in	O
clarifying	O
their	O
search	O
request	O
.	O
</s>
<s>
The	O
goal	O
is	O
to	O
provide	O
users	O
with	O
a	O
limited	O
number	O
of	O
relevant	O
results	O
,	O
as	O
opposed	O
to	O
traditional	O
search	B-Application
engines	I-Application
that	O
often	O
return	O
many	O
results	O
that	O
may	O
or	O
may	O
not	O
be	O
relevant	O
.	O
</s>
<s>
Examples	O
of	O
defunct	O
human	B-Application
search	I-Application
engines	I-Application
include	O
ApexKB	B-Protocol
,	O
ChaCha	B-Application
,	O
Mahalo.com,	O
NowNow	O
(	O
from	O
Amazon.com	B-Application
)	O
and	O
Sproose	B-Application
.	O
</s>
