<s>
ActivityPub	B-Operating_System
is	O
an	O
open	B-Application
,	O
decentralized	B-Operating_System
social	O
networking	O
protocol	O
based	O
on	O
io	O
's	O
ActivityPump	B-Operating_System
protocol	O
.	O
</s>
<s>
It	O
provides	O
a	O
client/server	B-Operating_System
API	B-Application
for	O
creating	O
,	O
updating	O
,	O
and	O
deleting	O
content	O
,	O
as	O
well	O
as	O
a	O
federated	O
server-to-server	B-Protocol
API	B-Application
for	O
delivering	O
notifications	O
and	O
content	O
.	O
</s>
<s>
ActivityPub	B-Operating_System
is	O
a	O
standard	O
for	O
the	O
Internet	O
in	O
the	O
Social	O
Web	O
Networking	O
Group	O
of	O
the	O
World	O
Wide	O
Web	O
Consortium	O
(	O
W3C	O
)	O
.	O
</s>
<s>
The	O
standard	O
was	O
co-authored	O
by	O
Evan	O
Prodromou	O
,	O
creator	O
of	O
StatusNet	B-Protocol
(	O
now	O
known	O
as	O
GNU	B-Protocol
social	I-Protocol
)	O
.	O
</s>
<s>
At	O
an	O
earlier	O
stage	O
,	O
the	O
name	O
of	O
the	O
protocol	O
was	O
"	O
ActivityPump	B-Operating_System
"	O
,	O
but	O
it	O
was	O
felt	O
that	O
ActivityPub	B-Operating_System
better	O
indicated	O
the	O
cross-publishing	O
purpose	O
of	O
the	O
protocol	O
.	O
</s>
<s>
It	O
learned	O
from	O
the	O
experiences	O
with	O
the	O
older	O
standard	O
called	O
OStatus	B-Application
.	O
</s>
<s>
It	O
is	O
the	O
most	O
widely	O
supported	O
standard	O
(	O
by	O
some	O
margin	O
)	O
in	O
the	O
Fediverse	B-Application
.	O
</s>
<s>
In	O
January	O
2018	O
,	O
the	O
World	O
Wide	O
Web	O
Consortium	O
(	O
W3C	O
)	O
published	O
the	O
ActivityPub	B-Operating_System
standard	O
as	O
a	O
Recommendation	O
.	O
</s>
<s>
She	O
also	O
notes	O
that	O
the	O
team	O
authoring	O
ActivityPub	B-Operating_System
had	O
no	O
corporate	O
participation	O
.	O
</s>
<s>
The	O
W3C	O
Social	O
Community	O
Group	O
organizes	O
a	O
yearly	O
free	O
conference	O
called	O
ActivityPub	B-Operating_System
Conf	O
about	O
the	O
future	O
of	O
ActivityPub	B-Operating_System
.	O
</s>
<s>
Former	O
Diaspora	O
community	O
manager	O
Sean	O
Tilley	O
wrote	O
an	O
article	O
that	O
suggests	O
ActivityPub	B-Operating_System
protocols	O
may	O
eventually	O
provide	O
a	O
way	O
to	O
federate	O
Internet	O
platforms	O
.	O
</s>
<s>
Friendica	B-Application
,	O
a	O
piece	O
of	O
social	O
networking	O
software	O
,	O
implemented	O
ActivityPub	B-Operating_System
in	O
version	O
2019.01	O
.	O
</s>
<s>
Mastodon	B-Application
,	O
a	O
social	O
networking	O
software	O
,	O
implemented	O
ActivityPub	B-Operating_System
in	O
version	O
1.6	O
,	O
released	O
in	O
September	O
2017	O
.	O
</s>
<s>
It	O
is	O
intended	O
that	O
ActivityPub	B-Operating_System
offers	O
more	O
security	O
for	O
private	O
messages	O
than	O
the	O
previous	O
OStatus	B-Application
protocol	O
does	O
.	O
</s>
<s>
Micro.blog	B-Protocol
,	O
a	O
microblogging	B-Application
social	O
network	O
,	O
added	O
support	O
for	O
ActivityPub	B-Operating_System
in	O
2018	O
and	O
enabled	O
by	O
default	O
for	O
new	O
users	O
in	O
October	O
2022	O
.	O
</s>
<s>
Nextcloud	B-General_Concept
,	O
a	O
federated	O
service	O
for	O
file	O
hosting	O
.	O
</s>
<s>
PeerTube	B-Application
,	O
a	O
federated	O
service	O
for	O
video	O
streaming	O
.	O
</s>
<s>
Pixelfed	B-Application
,	O
a	O
piece	O
of	O
social	O
networking	O
software	O
which	O
resembles	O
Instagram	O
,	O
is	O
a	O
software	O
service	O
implementing	O
ActivityPub	B-Operating_System
.	O
</s>
<s>
Pleroma	O
,	O
a	O
lightweight	O
fediverse	B-Application
server	O
that	O
implements	O
ActivityPub	B-Operating_System
as	O
of	O
its	O
first	O
release	O
.	O
</s>
<s>
In	O
November	O
2022	O
,	O
Tumblr	B-Application
announced	O
that	O
they	O
will	O
be	O
adding	O
support	O
.	O
</s>
