<s>
Parakey	B-Application
is	O
a	O
web-based	O
computer	O
user	O
interface	O
proposed	O
by	O
Firefox	B-Application
contributors	O
Blake	O
Ross	O
and	O
Joe	O
Hewitt	O
.	O
</s>
<s>
Ross	O
describes	O
it	O
as	O
"	O
a	O
Web	O
operating	B-General_Concept
system	I-General_Concept
that	O
can	O
do	O
everything	O
an	O
OS	B-General_Concept
can	O
do.	O
"	O
</s>
<s>
On	O
20	O
July	O
2007	O
Parakey	B-Application
was	O
bought	O
by	O
Facebook	O
for	O
an	O
undisclosed	O
sum	O
.	O
</s>
<s>
Parakey	B-Application
was	O
Facebook	O
,	O
Inc	O
's	O
first	O
acquisition	O
.	O
</s>
