<s>
A	O
review	B-Application
aggregator	I-Application
is	O
a	O
system	O
that	O
collects	O
reviews	O
and	O
ratings	O
of	O
products	O
and	O
services	O
(	O
such	O
as	O
films	O
,	O
books	O
,	O
video	O
games	O
,	O
music	O
,	O
software	O
,	O
hardware	O
,	O
and	O
cars	O
)	O
.	O
</s>
<s>
Review	B-Application
aggregation	I-Application
sites	O
have	O
begun	O
to	O
have	O
economic	O
effects	O
on	O
the	O
companies	O
that	O
create	O
or	O
manufacture	O
items	O
under	O
review	O
,	O
especially	O
in	O
certain	O
categories	O
such	O
as	O
electronic	O
games	O
,	O
which	O
are	O
expensive	O
to	O
purchase	O
.	O
</s>
<s>
This	O
is	O
often	O
done	O
using	O
a	O
business-facing	O
product	O
review	B-Application
aggregator	I-Application
.	O
</s>
