swarm.coiloptic.org is a Fediverse server ("instance") that uses the ActivityPub protocol for decentralised social media.
Users on swarm.coiloptic.org can follow/be followed/message/like/boost accounts on other ActivityPub servers, Snac or similar software (Sharkey, Misskey, Honk, Wafrn, Mastodon, GoToSocial, etc).