Apparently there is another social-networking protocol (that is not ActivityPub) that uses ActivityStreams, named:

Distributed Social Networking Protocol (DSNP)

...

https://en.wikipedia.org/wiki/Distributed_Social_Networking_Protocol

https://dsnp.org/

https://web.archive.org/web/20130910101658/http://www.complang.org/pipermail/dsnp-interest/

#ActivityStreams #DistributedSocialNetworkingProtocol #DSNP