<s>
Discourse	O
is	O
a	O
free	B-License
and	I-License
open-source	I-License
Internet	B-Application
forum	I-Application
software	I-Application
.	O
</s>
<s>
Features	O
include	O
support	O
for	O
threading	O
,	O
categorization	O
and	O
tagging	B-General_Concept
of	O
discussions	O
,	O
configurable	O
access	O
control	O
,	O
live	O
updates	O
,	O
expanding	O
link	O
previews	O
,	O
infinite	O
scrolling	O
,	O
and	O
real-time	O
notifications	O
.	O
</s>
<s>
It	O
allows	O
for	O
a	O
high	O
level	O
of	O
customizability	O
via	O
its	O
plugin	B-Application
architecture	I-Application
and	O
its	O
theming	B-Application
system	O
.	O
</s>
<s>
The	O
client	O
side	O
application	O
is	O
written	O
in	O
EmberJS	B-Language
.	O
</s>
<s>
The	O
server	O
side	O
is	O
written	O
in	O
Ruby	B-Application
on	I-Application
Rails	I-Application
and	O
backed	O
by	O
a	O
Postgres	B-Application
database	O
and	O
Redis	B-Operating_System
cache	O
.	O
</s>
<s>
Since	O
its	O
release	O
,	O
Discourse	O
has	O
been	O
undergoing	O
active	O
development	O
with	O
over	O
40,000	O
commits	B-Protocol
as	O
of	O
March	O
2022	O
.	O
</s>
<s>
Tags	B-General_Concept
are	O
a	O
lightweight	O
alternative	O
to	O
categories	O
,	O
but	O
they	O
can	O
also	O
be	O
used	O
in	O
conjunction	O
.	O
</s>
<s>
Unlike	O
the	O
heavy	O
walls	O
of	O
categories	O
,	O
tags	B-General_Concept
are	O
nimble	O
,	O
flexible	O
and	O
lightweight	O
.	O
</s>
<s>
Categories	O
and	O
tags	B-General_Concept
can	O
be	O
assigned	O
to	O
topics	O
which	O
makes	O
them	O
follow	O
the	O
security	O
rules	O
for	O
those	O
if	O
applicable	O
.	O
</s>
<s>
Discobot	O
is	O
a	O
customizable	O
bot	O
whose	O
purpose	O
is	O
onboarding	O
new	O
users	O
,	O
interactively	O
,	O
to	O
use	O
many	O
of	O
the	O
platform	O
's	O
features	O
like	O
bookmarking	O
a	O
topic	O
,	O
oneboxing	O
links	O
(	O
embedded	O
previews	O
)	O
,	O
adding	O
emojis	B-Application
,	O
using	O
mentions	B-Application
,	O
basic	O
formatting	O
,	O
uploading	O
images	O
to	O
a	O
reply	O
,	O
flagging	O
posts	O
and	O
using	O
the	O
search	O
function	O
.	O
</s>
<s>
Groups	O
can	O
be	O
used	O
to	O
manage	O
access	O
to	O
certain	O
categories	O
,	O
group	O
mentions	B-Application
as	O
well	O
as	O
group	O
messages	O
.	O
</s>
<s>
It	O
supports	O
plain-text	O
,	O
markdown	O
,	O
and	O
HTML	B-Language
.	O
</s>
<s>
The	O
"	O
#	O
"	O
character	O
creates	O
a	O
similar	O
panel	O
for	O
categories	O
and	O
tags	B-General_Concept
.	O
</s>
<s>
Discourse	O
is	O
extendable	O
via	O
plugins	B-Application
.	O
</s>
<s>
Plugins	B-Application
create	O
the	O
ability	O
to	O
modify	O
both	O
the	O
server	O
and	O
client	O
sides	O
of	O
the	O
application	O
.	O
</s>
<s>
BBCode	B-Language
which	O
adds	O
support	O
for	O
BBtags	B-Language
.	O
</s>
<s>
The	O
discourse	O
team	O
maintains	O
a	O
list	O
of	O
both	O
official	O
and	O
community	O
contributed	O
plugins	B-Application
on	O
the	O
official	O
support	O
forum	O
.	O
</s>
<s>
Discourse	O
is	O
backed	O
by	O
a	O
full	O
REST	B-Protocol
API	I-Protocol
.	O
</s>
<s>
The	O
developers	O
welcome	O
peer	O
audits	O
of	O
the	O
open	B-License
source	I-License
code	O
and	O
encourage	O
reporting	O
security	O
issues	O
.	O
</s>
<s>
DiscourseHub	O
is	O
the	O
official	O
,	O
open	B-License
source	I-License
Discourse	O
application	O
for	O
Android	B-Application
and	O
iOS	B-Application
devices	O
.	O
</s>
<s>
The	O
officially-provided	O
,	O
x86	B-Device
64	I-Device
Linux	B-Application
,	O
Docker	B-Language
images	O
are	O
the	O
supported	O
method	O
for	O
installing	O
Discourse	O
.	O
</s>
<s>
The	O
Docker-based	O
distribution	O
includes	O
the	O
web	O
server	O
(	O
which	O
is	O
based	O
on	O
nginx	B-Operating_System
and	O
Unicorn	B-Application
)	O
,	O
database	O
system	O
(	O
PostgreSQL	B-Application
)	O
,	O
cache	O
(	O
Redis	B-Operating_System
)	O
,	O
and	O
background	O
processing	O
services	O
(	O
Sidekiq	B-Application
)	O
.	O
</s>
<s>
Discourse	O
requires	O
an	O
outgoing	O
MTA	B-Protocol
and	O
does	O
not	O
provide	O
one	O
itself	O
.	O
</s>
<s>
Discourse	O
provides	O
an	O
optional	O
Docker	B-Language
image	O
for	O
an	O
incoming-only	O
MTA	B-Protocol
,	O
and	O
supports	O
receiving	O
email	O
via	O
POP3	B-Protocol
or	O
IMAP	B-Protocol
.	O
</s>
<s>
This	O
is	O
an	O
example	O
of	O
an	O
open	B-License
source	I-License
software	O
business	O
model	O
where	O
a	O
company	O
sells	O
professional	O
services	O
to	O
willing	O
customers	O
.	O
</s>
<s>
As	O
of	O
March	O
2022	O
,	O
the	O
developers	O
shared	O
that	O
more	O
than	O
3000	O
businesses	O
or	O
instances	O
have	O
chosen	O
the	O
official	O
Discourse	O
hosting	O
which	O
CDCK	O
provides	O
as	O
Software	B-Architecture
as	I-Architecture
a	I-Architecture
service	I-Architecture
.	O
</s>
