<s>
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
(	O
DotA	B-Operating_System
)	O
is	O
a	O
multiplayer	O
online	O
battle	O
arena	O
(	O
MOBA	O
)	O
mod	O
for	O
the	O
video	O
game	O
Warcraft	B-Application
III	I-Application
:	I-Application
Reign	I-Application
of	I-Application
Chaos	I-Application
(	O
2002	O
)	O
and	O
its	O
expansion	O
,	O
The	B-Application
Frozen	I-Application
Throne	I-Application
.	O
</s>
<s>
Players	O
use	O
powerful	O
units	O
known	O
as	O
heroes	O
,	O
and	O
are	O
assisted	O
by	O
allied	O
teammates	O
and	O
AI-controlled	O
fighters	O
.	O
</s>
<s>
DotA	B-Operating_System
has	O
its	O
roots	O
in	O
the	O
"	O
Aeon	O
of	O
Strife	O
"	O
custom	O
map	O
for	O
StarCraft	B-Application
.	O
</s>
<s>
The	O
scenario	O
was	O
developed	O
with	O
the	O
World	O
Editor	O
of	O
Reign	B-Application
of	I-Application
Chaos	I-Application
,	O
and	O
was	O
updated	O
upon	O
the	O
release	O
of	O
its	O
expansion	O
,	O
The	B-Application
Frozen	I-Application
Throne	I-Application
.	O
</s>
<s>
There	O
have	O
been	O
many	O
variations	O
of	O
the	O
original	O
concept	O
,	O
the	O
most	O
popular	O
being	O
DotA	B-Operating_System
Allstars	I-Operating_System
,	O
eventually	O
simplified	O
to	O
DotA	B-Operating_System
.	O
</s>
<s>
DotA	B-Operating_System
became	O
a	O
feature	O
at	O
several	O
worldwide	O
tournaments	O
,	O
including	O
Blizzard	O
Entertainment	O
's	O
BlizzCon	O
and	O
the	O
Asian	O
World	O
Cyber	O
Games	O
.	O
</s>
<s>
Critical	O
reception	O
to	O
DotA	B-Operating_System
was	O
positive	O
,	O
and	O
it	O
has	O
been	O
called	O
one	O
of	O
the	O
most	O
popular	O
mods	O
of	O
any	O
game	O
.	O
</s>
<s>
DotA	B-Operating_System
is	O
largely	O
attributed	O
as	O
being	O
the	O
most	O
significant	O
inspiration	O
for	O
the	O
MOBA	O
genre	O
.	O
</s>
<s>
American	O
video	O
game	O
developer	O
Valve	O
acquired	O
the	O
intellectual	O
property	O
rights	O
to	O
DotA	B-Operating_System
in	O
2009	O
to	O
develop	O
a	O
franchise	B-Operating_System
,	O
beginning	O
with	O
Dota	B-Application
2	I-Application
in	O
2013	O
.	O
</s>
<s>
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
pits	O
two	O
teams	O
of	O
players	O
against	O
each	O
other	O
.	O
</s>
<s>
In	O
DotA	B-Operating_System
,	O
players	O
on	O
each	O
side	O
can	O
choose	O
one	O
of	O
more	O
than	O
a	O
hundred	O
heroes	O
,	O
each	O
with	O
different	O
abilities	O
and	O
tactical	O
advantages	O
.	O
</s>
<s>
DotA	B-Operating_System
allows	O
up	O
to	O
ten	O
players	O
in	O
a	O
five-versus-five	O
format	O
.	O
</s>
<s>
The	O
typical	O
resource-gathering	O
of	O
Warcraft	B-Application
III	I-Application
is	O
replaced	O
by	O
a	O
combat-oriented	O
money	O
system	O
;	O
in	O
addition	O
to	O
a	O
small	O
periodic	O
income	O
,	O
heroes	O
earn	O
gold	O
by	O
killing	O
or	O
destroying	O
hostile	O
units	O
,	O
base	O
structures	O
,	O
and	O
enemy	O
heroes	O
.	O
</s>
<s>
DotA	B-Operating_System
offers	O
a	O
variety	O
of	O
game	O
modes	O
,	O
selected	O
by	O
the	O
game	O
host	O
at	O
the	O
beginning	O
of	O
the	O
match	O
.	O
</s>
<s>
Blizzard	O
Entertainment	O
's	O
1998	O
real-time	O
strategy	O
game	O
StarCraft	B-Application
shipped	O
with	O
a	O
campaign	O
editor	O
that	O
allowed	O
players	O
to	O
create	O
custom	O
levels	O
,	O
complete	O
with	O
scripted	O
triggers	O
.	O
</s>
<s>
Blizzard	O
followed	O
StarCraft	B-Application
with	O
the	O
real-time	O
strategy	O
game	O
Warcraft	B-Application
III	I-Application
in	O
2002	O
.	O
</s>
<s>
As	O
with	O
Warcraft	B-Application
II	I-Application
and	O
StarCraft	B-Application
,	O
Blizzard	O
included	O
a	O
free	O
World	O
Editor	O
in	O
the	O
game	O
that	O
allows	O
players	O
to	O
create	O
custom	O
scenarios	O
or	O
maps	O
for	O
the	O
game	O
,	O
which	O
can	O
be	O
played	O
online	O
with	O
other	O
players	O
through	O
Battle.net	B-Operating_System
.	O
</s>
<s>
Warcraft	B-Application
III	I-Application
also	O
featured	O
powerful	O
hero	O
units	O
that	O
leveled	O
up	O
and	O
could	O
equip	O
items	O
to	O
boost	O
their	O
abilities	O
,	O
and	O
the	O
World	O
Editor	O
enabled	O
mapmakers	O
to	O
create	O
their	O
own	O
.	O
</s>
<s>
Taking	O
inspiration	O
from	O
Aeon	O
of	O
Strife	O
and	O
using	O
the	O
expanded	O
capabilities	O
of	O
the	O
World	O
Editor	O
,	O
modder	O
Kyle	O
"	O
Eulogizing	O
"	O
Sommer	O
created	O
the	O
first	O
version	O
of	O
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
in	O
2003	O
.	O
</s>
<s>
After	O
the	O
release	O
of	O
Warcraft	B-Application
IIIs	I-Application
expansion	O
The	B-Application
Frozen	I-Application
Throne	I-Application
,	O
which	O
added	O
new	O
features	O
to	O
the	O
World	O
Editor	O
,	O
Eul	O
did	O
not	O
update	O
the	O
scenario	O
and	O
made	O
his	O
map	O
code	O
open-source	O
.	O
</s>
<s>
Other	O
mapmakers	O
produced	O
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
spinoffs	O
that	O
added	O
new	O
heroes	O
,	O
items	O
,	O
and	O
features	O
.	O
</s>
<s>
Among	O
the	O
DotA	B-Operating_System
variants	O
created	O
in	O
the	O
wake	O
of	O
Eul	O
's	O
map	O
,	O
there	O
was	O
DotA	B-Operating_System
Allstars	I-Operating_System
,	O
originally	O
created	O
and	O
developed	O
by	O
custom	O
map	O
makers	O
Meian	O
and	O
Ragn0r	O
,	O
who	O
took	O
the	O
most	O
popular	O
heroes	O
and	O
compiled	O
them	O
into	O
one	O
map	O
.	O
</s>
<s>
In	O
March	O
2004	O
,	O
map	O
maker	O
Steve	O
"	O
Guinsoo	B-Operating_System
"	O
Feak	O
assumed	O
control	O
of	O
Allstars	O
development	O
.	O
</s>
<s>
Feak	O
said	O
when	O
he	O
began	O
developing	O
DotA	B-Operating_System
Allstars	I-Operating_System
,	O
he	O
had	O
no	O
idea	O
how	O
popular	O
the	O
game	O
would	O
eventually	O
become	O
.	O
</s>
<s>
Feak	O
used	O
a	O
Battle.net	B-Operating_System
chat	O
channel	O
as	O
a	O
place	O
for	O
DotA	B-Operating_System
players	O
to	O
congregate	O
,	O
but	O
DotA	B-Operating_System
Allstars	I-Operating_System
had	O
no	O
official	O
site	O
for	O
discussions	O
and	O
hosting	O
.	O
</s>
<s>
Subsequently	O
,	O
the	O
leaders	O
of	O
the	O
DotA	B-Operating_System
Allstars	I-Operating_System
clan	O
,	O
TDA	O
,	O
proposed	O
that	O
a	O
dedicated	O
web	O
site	O
be	O
created	O
to	O
replace	O
the	O
various	O
online	O
alternatives	O
that	O
were	O
infrequently	O
updated	O
or	O
improperly	O
maintained	O
.	O
</s>
<s>
TDA	O
member	O
Steve	O
"	O
Pendragon	O
"	O
Mescon	O
created	O
an	O
official	O
community	O
site	O
,	O
dota-allstars.com	O
.	O
</s>
<s>
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
was	O
maintained	O
via	O
official	O
forums	O
.	O
</s>
<s>
Mescon	O
maintained	O
dota-allstars.com,	O
which	O
by	O
May	O
2009	O
had	O
over	O
1,500,000	O
registered	O
users	O
and	O
received	O
over	O
one	O
million	O
unique	O
visitors	O
every	O
month	O
.	O
</s>
<s>
Mescon	O
's	O
sale	O
of	O
the	O
domain	O
to	O
Riot	O
Games	O
split	O
the	O
DotA	B-Operating_System
community	O
,	O
and	O
IceFrog	O
announced	O
a	O
new	O
official	O
site	O
,	O
playdota.com,	O
while	O
continuing	O
game	O
development	O
.	O
</s>
<s>
Because	O
Warcraft	B-Application
III	I-Application
custom	O
games	O
have	O
none	O
of	O
the	O
features	O
designed	O
to	O
improve	O
game	O
quality	O
(	O
matchmaking	O
players	O
based	O
on	O
connection	O
speed	O
,	O
etc	O
.	O
</s>
<s>
)	O
,	O
various	O
programs	O
were	O
used	O
to	O
maintain	O
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
.	O
</s>
<s>
While	O
increasingly	O
popular	O
,	O
DotA	B-Operating_System
Allstars	I-Operating_System
remained	O
limited	O
as	O
a	O
custom	O
map	O
in	O
Warcraft	B-Application
III	I-Application
,	O
relying	O
on	O
manual	O
matchmaking	O
,	O
updates	O
,	O
and	O
containing	O
no	O
tutorials	O
.	O
</s>
<s>
Computer	O
Gaming	O
World	O
featured	O
DotA	B-Operating_System
Allstars	I-Operating_System
in	O
a	O
2004	O
review	O
of	O
new	O
maps	O
and	O
mods	O
in	O
Warcraft	B-Application
III	I-Application
,	O
and	O
in	O
the	O
following	O
years	O
DotA	B-Operating_System
Allstars	I-Operating_System
became	O
a	O
fixture	O
at	O
esports	O
tournaments	O
.	O
</s>
<s>
DotA	B-Operating_System
Allstars	I-Operating_System
was	O
also	O
featured	O
in	O
the	O
Malaysia	O
and	O
Singapore	O
World	O
Cyber	O
Games	O
starting	O
in	O
2005	O
,	O
and	O
the	O
World	O
Cyber	O
Games	O
Asian	O
Championships	O
beginning	O
with	O
the	O
2006	O
season	O
.	O
</s>
<s>
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
was	O
included	O
in	O
the	O
game	O
lineup	O
for	O
the	O
internationally	O
recognized	O
Cyberathlete	O
Amateur	O
League	O
and	O
CyberEvolution	O
leagues	O
.	O
</s>
<s>
In	O
the	O
Philippines	O
and	O
Thailand	O
,	O
it	O
was	O
played	O
as	O
much	O
as	O
the	O
game	O
Counter-Strike	B-Application
.	O
</s>
<s>
It	O
was	O
also	O
popular	O
in	O
Sweden	O
and	O
other	O
Northern	O
European	O
countries	O
,	O
where	O
the	O
Defense	O
of	O
the	O
Ancients-inspired	O
song	O
"	O
Vi	O
sitter	O
i	O
Ventrilo	O
och	O
spelar	O
DotA	B-Operating_System
"	O
by	O
Swedish	O
musician	O
Basshunter	O
cracked	O
the	O
top	O
ten	O
singles	O
charts	O
in	O
Sweden	O
,	O
Norway	O
,	O
and	O
Finland	O
.	O
</s>
<s>
LAN	B-General_Concept
tournaments	O
were	O
a	O
major	O
part	O
of	O
worldwide	O
play	O
,	O
including	O
tournaments	O
in	O
Sweden	O
and	O
Russia	O
;	O
however	O
,	O
due	O
to	O
a	O
lack	O
of	O
LAN	B-General_Concept
tournaments	O
and	O
championships	O
in	O
North	O
America	O
,	O
several	O
teams	O
disbanded	O
.	O
</s>
<s>
Michael	O
Walbridge	O
,	O
writing	O
for	O
Gamasutra	O
in	O
2008	O
,	O
stated	O
that	O
DotA	B-Operating_System
"	O
is	O
likely	O
the	O
most	O
popular	O
and	O
most-discussed	O
free	O
,	O
non-supported	O
game	O
mod	O
in	O
the	O
world	O
"	O
.	O
</s>
<s>
In	O
pointing	O
to	O
the	O
strong	O
community	O
built	O
around	O
the	O
game	O
,	O
Walbridge	O
stated	O
that	O
DotA	B-Operating_System
showed	O
it	O
is	O
much	O
easier	O
for	O
a	O
community	O
game	O
to	O
be	O
maintained	O
by	O
the	O
community	O
,	O
and	O
this	O
is	O
one	O
of	O
the	O
maps	O
 '	O
greatest	O
strengths	O
.	O
</s>
<s>
Former	O
game	O
journalist	O
Luke	O
Smith	O
called	O
DotA	B-Operating_System
"	O
the	O
ultimate	O
RTS	O
"	O
.	O
</s>
<s>
Blizzard	O
pointed	O
to	O
DotA	B-Operating_System
as	O
an	O
example	O
of	O
what	O
dedicated	O
mapmakers	O
can	O
create	O
using	O
developer	O
's	O
tools	O
.	O
</s>
<s>
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
helped	O
spur	O
the	O
development	O
of	O
the	O
multiplayer	O
online	O
battle	O
arena	O
(	O
MOBA	O
)	O
genre	O
.	O
</s>
<s>
It	O
was	O
one	O
of	O
the	O
influences	O
for	O
the	O
2009	O
Gas	O
Powered	O
Games	O
title	O
Demigod	B-Language
,	O
with	O
the	O
video	O
game	O
publication	O
GameSpy	O
noting	O
the	O
game	O
's	O
premise	O
revolved	O
around	O
aspiring	O
gods	O
"[playing]	O
DotA	B-Operating_System
in	O
real	O
life	O
"	O
.	O
</s>
<s>
Feak	O
went	O
on	O
to	O
apply	O
many	O
of	O
the	O
mechanics	O
and	O
lessons	O
he	O
learned	O
from	O
Defense	B-Operating_System
of	I-Operating_System
the	I-Operating_System
Ancients	I-Operating_System
to	O
the	O
Riot	O
Games	O
title	O
League	B-Application
of	I-Application
Legends	I-Application
.	O
</s>
<s>
Other	O
"	O
DotA	B-Operating_System
clones	O
"	O
include	O
S2	O
Games	O
 '	O
Heroes	B-Application
of	I-Application
Newerth	I-Application
.	O
</s>
<s>
Blizzard	O
Entertainment	O
developed	O
a	O
game	O
inspired	O
by	O
DotA	B-Operating_System
titled	O
Heroes	B-Application
of	I-Application
the	I-Application
Storm	I-Application
,	O
which	O
features	O
an	O
array	O
of	O
heroes	O
from	O
Blizzard	O
's	O
franchises	O
,	O
including	O
numerous	O
heroes	O
from	O
Warcraft	B-Application
III	I-Application
.	O
</s>
<s>
The	O
MOBA	O
design	O
DotA	B-Operating_System
popularized	O
also	O
made	O
its	O
way	O
into	O
games	O
that	O
deviated	O
from	O
the	O
mod	O
's	O
top-down	O
perspective	O
,	O
such	O
as	O
third-person	O
shooters	O
and	O
side-scrolling	O
platformers	O
.	O
</s>
<s>
DotA	B-Operating_System
also	O
typified	O
the	O
MOBA	O
genre	O
's	O
reputation	O
for	O
unfriendly	O
and	O
toxic	O
behavior	O
as	O
well	O
as	O
a	O
difficult	O
learning	O
curve	O
for	O
new	O
players	O
.	O
</s>
<s>
In	O
October	O
2009	O
,	O
IceFrog	O
was	O
hired	O
by	O
Valve	O
to	O
lead	O
a	O
team	O
to	O
develop	O
the	O
standalone	O
sequel	O
,	O
Dota	B-Application
2	I-Application
.	O
</s>
<s>
The	O
game	O
follows	O
heavily	O
in	O
the	O
gameplay	O
style	O
of	O
DotA	B-Operating_System
,	O
with	O
aesthetics	O
and	O
heroes	O
working	O
mostly	O
as	O
direct	O
ports	O
to	O
the	O
original	O
mod	O
.	O
</s>
<s>
In	O
addition	O
to	O
the	O
pre-conceived	O
gameplay	O
constants	O
,	O
Dota	B-Application
2	I-Application
also	O
features	O
Steam	B-Application
support	O
and	O
profile	O
tracking	O
,	O
intended	O
to	O
emphasize	O
and	O
support	O
the	O
game	O
's	O
matchmaking	O
and	O
community	O
.	O
</s>
<s>
The	O
marketing	O
and	O
trademark	O
of	O
Dota	B-Operating_System
as	O
a	O
franchise	B-Operating_System
by	O
Valve	O
faced	O
opposition	O
from	O
the	O
DotA	B-Operating_System
Allstars	I-Operating_System
contributors	O
working	O
at	O
Riot	O
Games	O
,	O
as	O
well	O
as	O
Blizzard	O
Entertainment	O
,	O
both	O
of	O
which	O
legally	O
challenged	O
the	O
franchising	O
of	O
Dota	B-Operating_System
by	O
Valve	O
.	O
</s>
<s>
Dota	B-Application
2	I-Application
was	O
officially	O
released	O
in	O
July	O
2013	O
.	O
</s>
