If you want to see the Facebook thread that most directly (there were schemes and ideas beforehand) resulted in #SocialCoop, check this #PrimarySource: https://www.facebook.com/groups/p2p.open/permalink/1448639075180267/
It's interesting to see what concerns at the time (2017) are still discussed, and what seems to have faded from consciousness since then (in particular, concerns about the same handle on multiple instances).
Also, #DmytriKeleiner has popped onto the zombie thread for some light trolling... :P
social.coop is a cooperatively-run corner of the Fediverse. The instance is democratically governed by its members, who generally share an interest in the co-op model, but topics of discussion range widely.
Our instance is supported by sliding scale contributions of $1-10/mo made via Open Collective. You must have an active Open Collective account to apply for membership; you may set one up here