<s>
A	O
closed	B-Application
platform	I-Application
,	O
walled	B-Application
garden	I-Application
,	O
or	O
closed	B-Application
ecosystem	I-Application
is	O
a	O
software	O
system	O
wherein	O
the	O
carrier	O
or	O
service	O
provider	O
has	O
control	O
over	O
applications	B-Application
,	O
content	O
,	O
and/or	O
media	O
,	O
and	O
restricts	O
convenient	O
access	O
to	O
non-approved	O
applicants	O
or	O
content	O
.	O
</s>
<s>
This	O
is	O
in	O
contrast	O
to	O
an	O
open	B-Application
platform	I-Application
,	O
wherein	O
consumers	O
generally	O
have	O
unrestricted	O
access	O
to	O
applications	B-Application
and	O
content	O
.	O
</s>
<s>
For	O
example	O
,	O
in	O
telecommunications	O
,	O
the	O
services	O
and	O
applications	B-Application
accessible	O
on	O
a	O
cell	O
phone	O
on	O
any	O
given	O
wireless	O
device	O
were	O
formerly	O
tightly	O
controlled	O
by	O
the	O
mobile	O
operators	O
.	O
</s>
<s>
The	O
operators	O
limited	O
the	O
applications	B-Application
and	O
developers	O
that	O
were	O
available	O
on	O
users	O
 '	O
home	O
portals	O
and	O
home	O
pages	O
.	O
</s>
<s>
This	O
has	O
long	O
been	O
a	O
central	O
issue	O
constraining	O
the	O
telecommunications	O
sector	O
,	O
as	O
developers	O
face	O
huge	O
hurdles	O
in	O
making	O
their	O
applications	B-Application
available	O
to	O
end-users	O
.	O
</s>
<s>
More	O
generally	O
,	O
a	O
walled	B-Application
garden	I-Application
can	O
refer	O
to	O
a	O
closed	O
or	O
exclusive	O
set	O
of	O
information	O
services	O
provided	O
for	O
users	O
.	O
</s>
<s>
Similar	O
to	O
a	O
real	O
walled	B-Application
garden	I-Application
,	O
a	O
user	O
is	O
unable	O
to	O
escape	O
this	O
closed	O
environment	O
except	O
through	O
the	O
designated	O
entry/exit	O
points	O
or	O
if	O
the	O
walls	O
are	O
removed	O
.	O
</s>
<s>
Some	O
examples	O
of	O
walled	B-Application
gardens	I-Application
include	O
:	O
</s>
<s>
In	O
the	O
1990s	O
,	O
AOL	O
developed	O
what	O
later	O
was	O
called	O
its	O
"	O
walled	B-Application
garden	I-Application
"	O
model	O
of	O
service	O
.	O
</s>
<s>
Amazon	B-Application
's	O
Kindle	B-General_Concept
line	O
of	O
eReaders	O
.	O
</s>
<s>
As	O
an	O
October	O
2011	O
Business	O
Insider	O
article	O
,	O
entitled	O
"	O
How	O
Amazon	B-Application
Makes	O
Money	O
From	O
The	B-General_Concept
Kindle	I-General_Concept
"	O
observes	O
:	O
"	O
Amazon	B-Application
's	O
Kindle	B-General_Concept
is	O
no	O
longer	O
just	O
a	O
product	O
:	O
It	O
's	O
a	O
whole	O
ecosystem.	O
"	O
</s>
<s>
Moreover	O
,	O
as	O
Business	O
Insider	O
noted	O
"	O
The	B-General_Concept
Kindle	I-General_Concept
ecosystem	O
is	O
also	O
Amazon	B-Application
's	O
fastest-growing	O
product	O
and	O
could	O
account	O
for	O
more	O
than	O
10%	O
of	O
the	O
company	O
's	O
revenue	O
next	O
year.	O
"	O
</s>
<s>
Apple	B-Operating_System
iOS	I-Operating_System
and	O
other	O
mobile	O
devices	O
,	O
which	O
are	O
restricted	O
to	O
running	O
pre-approved	O
applications	B-Application
from	O
a	O
digital	O
distribution	O
service	O
.	O
</s>
<s>
Barnes	O
&	O
Noble	O
's	O
Nook	B-Application
devices	O
.	O
</s>
<s>
In	O
late	O
December	O
2011	O
,	O
B&N	O
began	O
pushing	O
the	O
automatic	O
,	O
over-the-air	O
firmware	O
update	O
1.4.1	O
to	O
Nook	B-Application
Tablets	O
that	O
removed	O
users	O
 '	O
ability	O
to	O
gain	O
root	B-Application
access	I-Application
to	O
the	O
device	O
and	O
the	O
ability	O
to	O
sideload	B-Protocol
applications	B-Application
from	O
sources	O
other	O
than	O
the	O
official	O
Barnes	B-Application
and	I-Application
Noble	I-Application
NOOK	I-Application
Store	O
(	O
without	O
modding	B-Device
)	O
.	O
</s>
<s>
Nook	B-Application
HD	I-Application
devices	O
were	O
similarly	O
"	O
closed	O
"	O
,	O
until	O
May	O
2013	O
,	O
when	O
BN	O
opened	O
its	O
ecosystem	O
somewhat	O
by	O
permitting	O
users	O
to	O
install	O
the	B-Application
Google	I-Application
Play	B-Application
Store	I-Application
and	O
the	O
various	O
Android	B-Application
apps	O
offered	O
there	O
,	O
including	O
those	O
of	O
rivals	O
,	O
such	O
as	O
Audible.com,	O
ComiXology	B-Application
,	O
Kindle	B-General_Concept
,	O
Kobo	O
,	O
and	O
Google	B-Application
itself	O
.	O
</s>
<s>
The	O
Encrypted	B-Language
Media	I-Language
Extensions	I-Language
specification	O
provides	O
APIs	B-Application
to	O
control	O
playback	O
of	O
encrypted	O
content	O
.	O
</s>
<s>
This	O
is	O
part	O
of	O
the	O
World	O
Wide	O
Web	O
Consortium	O
's	O
web	O
standards	O
and	O
was	O
authored	O
by	O
members	O
working	O
from	O
Google	B-Application
,	O
Microsoft	O
and	O
Netflix	O
.	O
</s>
<s>
Kwangmyong	B-Language
,	O
the	O
national	B-Application
intranet	I-Application
service	O
that	O
operates	O
in	O
North	O
Korea	O
.	O
</s>
<s>
It	O
operates	O
as	O
a	O
"	O
walled	B-Application
garden	I-Application
"	O
network	O
,	O
as	O
no	O
information	O
is	O
permitted	O
to	O
enter	O
the	O
network	O
without	O
government	O
approval	O
.	O
</s>
<s>
Verizon	B-Application
Wireless	I-Application
 '	O
CDMA	B-Protocol
network	O
and	O
policies	O
effectively	O
prohibiting	O
activation	O
of	O
non-Verizon	O
sanctioned	O
devices	O
on	O
their	O
network	O
.	O
</s>
<s>
Verizon	B-Application
Wireless	I-Application
is	O
frequently	O
noted	O
(	O
and	O
often	O
criticized	O
)	O
for	O
this	O
practice	O
.	O
</s>
<s>
Permissioned	O
blockchains	O
have	O
been	O
called	O
the	O
“	O
walled	B-Application
gardens	I-Application
”	O
of	O
2017	O
.	O
</s>
<s>
Video	B-Device
game	I-Device
consoles	I-Device
have	O
a	O
long	O
history	O
of	O
walled	B-Application
gardens	I-Application
,	O
with	O
developers	O
needing	O
to	O
purchase	O
licences	O
to	O
develop	O
for	O
the	O
platform	O
,	O
and	O
,	O
in	O
some	O
cases	O
,	O
needing	O
editorial	O
approval	O
from	O
the	O
console	O
manufacturer	O
prior	O
to	O
publishing	O
games	O
.	O
</s>
<s>
Super-apps	B-Application
such	O
as	O
WeChat	B-Application
have	O
been	O
called	O
walled	B-Application
gardens	I-Application
by	O
critics	O
.	O
</s>
