<s>
Hyperlink-Induced	B-Application
Topic	I-Application
Search	I-Application
(	O
HITS	O
;	O
also	O
known	O
as	O
hubs	B-Application
and	I-Application
authorities	I-Application
)	O
is	O
a	O
link	B-Application
analysis	I-Application
algorithm	O
that	O
rates	O
Web	O
pages	O
,	O
developed	O
by	O
Jon	O
Kleinberg	O
.	O
</s>
<s>
The	O
idea	O
behind	O
Hubs	B-Application
and	I-Application
Authorities	I-Application
stemmed	O
from	O
a	O
particular	O
insight	O
into	O
the	O
creation	O
of	O
web	O
pages	O
when	O
the	O
Internet	O
was	O
originally	O
forming	O
;	O
that	O
is	O
,	O
certain	O
web	O
pages	O
,	O
known	O
as	O
hubs	O
,	O
served	O
as	O
large	O
directories	O
that	O
were	O
not	O
actually	O
authoritative	O
in	O
the	O
information	O
that	O
they	O
held	O
,	O
but	O
were	O
used	O
as	O
compilations	O
of	O
a	O
broad	O
catalog	O
of	O
information	O
that	O
led	O
users	O
direct	O
to	O
other	O
authoritative	O
pages	O
.	O
</s>
<s>
Counting	O
the	O
number	O
of	O
links	O
to	O
a	O
page	O
can	O
give	O
us	O
a	O
general	O
estimate	O
of	O
its	O
prominence	O
on	O
the	O
Web	O
,	O
but	O
a	O
page	O
with	O
very	O
few	O
incoming	O
links	O
may	O
also	O
be	O
prominent	O
,	O
if	O
two	O
of	O
these	O
links	O
come	O
from	O
the	O
home	O
pages	O
of	O
sites	O
like	O
Yahoo	O
!,	O
Google	B-Application
,	O
or	O
MSN	B-Protocol
.	O
</s>
<s>
Because	O
these	O
sites	O
are	O
of	O
very	O
high	O
importance	O
but	O
are	O
also	O
search	B-Application
engines	I-Application
,	O
a	O
page	O
can	O
be	O
ranked	O
much	O
higher	O
than	O
its	O
actual	O
relevance	O
.	O
</s>
<s>
In	O
the	O
HITS	B-Application
algorithm	I-Application
,	O
the	O
first	O
step	O
is	O
to	O
retrieve	O
the	O
most	O
relevant	O
pages	O
to	O
the	O
search	O
query	O
.	O
</s>
<s>
Authority	O
and	O
hub	O
values	O
are	O
defined	O
in	O
terms	O
of	O
one	O
another	O
in	O
a	O
mutual	B-Algorithm
recursion	I-Algorithm
.	O
</s>
<s>
HITS	O
,	O
like	O
Page	O
and	O
Brin	O
's	O
PageRank	B-Algorithm
,	O
is	O
an	O
iterative	B-Algorithm
algorithm	I-Algorithm
based	O
on	O
the	O
linkage	O
of	O
the	O
documents	O
on	O
the	O
web	O
.	O
</s>
<s>
It	O
is	O
processed	O
on	O
a	O
small	O
subset	O
of	O
‘	O
relevant’	O
documents	O
(	O
a	O
'	O
focused	O
subgraph	O
 '	O
or	O
base	O
set	O
)	O
,	O
instead	O
of	O
the	O
set	O
of	O
all	O
documents	O
as	O
was	O
the	O
case	O
with	O
PageRank	B-Algorithm
.	O
</s>
<s>
It	O
is	O
not	O
commonly	O
used	O
by	O
search	B-Application
engines	I-Application
.	O
</s>
<s>
(	O
Though	O
a	O
similar	O
algorithm	O
was	O
said	O
to	O
be	O
used	O
by	O
Teoma	B-Application
,	O
which	O
was	O
acquired	O
by	O
Ask	B-Application
Jeeves/Ask.com	I-Application
.	O
)	O
</s>
