<s>
Meta	B-Application
Content	I-Application
Framework	I-Application
(	O
MCF	O
)	O
is	O
a	O
specification	O
of	O
a	O
content	O
format	O
for	O
structuring	O
metadata	O
about	O
web	O
sites	O
and	O
other	O
data	O
.	O
</s>
<s>
Rooted	O
in	O
knowledge-representation	O
systems	O
such	O
as	O
CycL	B-Language
,	O
KRL	B-Language
,	O
and	O
KIF	B-Language
,	O
it	O
sought	O
to	O
describe	O
objects	O
,	O
their	O
attributes	O
,	O
and	O
the	O
relationships	O
between	O
them	O
.	O
</s>
<s>
One	O
application	O
of	O
MCF	O
was	O
HotSauce	B-Application
,	O
also	O
developed	O
by	O
Guha	O
while	O
at	O
Apple	O
.	O
</s>
<s>
It	O
generated	O
a	O
3D	B-Application
visualization	I-Application
of	O
a	O
web	O
site	O
's	O
table	O
of	O
contents	O
,	O
based	O
on	O
MCF	O
descriptions	O
.	O
</s>
<s>
By	O
late	O
1996	O
,	O
a	O
few	O
hundred	O
sites	O
were	O
creating	O
MCF	O
files	O
and	O
Apple	B-Application
HotSauce	I-Application
allowed	O
users	O
to	O
browse	O
these	O
MCF	O
representations	O
in	O
3D	O
.	O
</s>
<s>
When	O
the	O
research	O
project	O
was	O
discontinued	O
,	O
Guha	O
left	O
Apple	O
for	O
Netscape	O
,	O
where	O
,	O
in	O
collaboration	O
with	O
Tim	O
Bray	O
,	O
he	O
adapted	O
MCF	O
to	O
use	O
XML	B-Protocol
and	O
created	O
the	O
first	O
version	O
of	O
the	O
Resource	O
Description	O
Framework	O
(	O
RDF	O
)	O
.	O
</s>
