Pediverse
The Pediverse (a portmanteau of "pedophile" and "universe") is an ensemble of federated (i.e. interconnected) servers that are used by pedophiles, hebephiles, other MAPs and allies for web publishing (i.e. social networking, microblogging, blogging, or websites) and file hosting.
While independently hosted, profiles on these servers can communicate with each other, although one server owner may freely decide to block other servers, or promote particular servers to their userbase. On different servers (technically instances), pediverse users can create profiles on what are typically open-source social media platforms modeled on popular socials such as Twitter. These profiles are able to communicate over the boundaries of the instances because the software running on the servers supports one or more communication protocols that follow an open standard.
As an identity on the pediverse, users are able to post text and other media, or to follow posts by other identities. In some cases, users can show or share data (video, audio, text, and other files) publicly or to a selected group of identities, and allow other identities to edit other users' data (such as a calendar or an address book).
Pediverse players
MAPs have been proactive in setting up federated/decentralized communication platforms, because of well-founded fears centering on censorship and harassment, mental health and validity policing.
Social
These are the better-known social instances, all of which permit communication with one another, and prohibit CP sharing and other illegal activity.
NNIA.space
Nnia.space, created May 2020. Runs on Mastodon. Anti-contact predominates, restrictions on contact debate/discourse.
Freak.university
Similar to NNIA (runs on Mastodon), with less restrictions on discourse. According to them, their userbase "includes paraphiles, the mentally ill, queer folk, transX folk, and people with any other non-normative or heavily stigmatized identity."