A silly microblogging site, like Twitter but for crabs.
Pleroma is a free, federated social networking server built on open protocols. It is compatible with GNU Social, Mastodon, and many other ActivityPub implementations.
The project consists of several components: Pleroma is the server implementation, and comes bundled with PleromaFE, the default frontend. Other useful utilities are also provided, such as an ActivityPub relay.
High performance, low latency, you can even run it on a RasPi (and many busy Pleroma instances are!)
Written in Elixir and Phoenix, with Postgres as its back-end.
Source code: https://git.pleroma.social/pleroma/pleroma/
Movim is a decentralized social platform, written in PHP and HTML5 and based on XMPP. Database backend for caching. Seems suited for not-shared hosting because php-fpm is recommended, as well as Websockets and a long-running daemon (which shared hosting providers like Dreamhost don't like and kill automatically). Seems to require experienced webapp admins because knowledge of the application architecture is required.
Requires that the server support XEP-0060 (pubsub) because message transfer is built on top of it.
Keyoxide allows you to link accounts on various online services and platforms together, prove they belong to you and establish an online identity. This puts you, the internet citizen, in charge when it comes to defining who you are on the internet instead of large corporations.
Seems a lot like Keybase.
Source code: https://codeberg.org/keyoxide/web
Seems like it's written in PHP. Could be a lot worse.
An ultra-slim microblogging package for hackers. CLI or bust. Open system - uses text files in public places, so there. Tracks the directories of twtxt users and aggregates them into a timeline. Written in Python3. Integrates with the usual shell environments. Simple enough that people have written their own implementations.
Distinct from jointwt/twtxt! Do not delete this bookmark!
Maybe it can be repurposed as a message bus for stuff?
A Mastodon instance for Homestuck.
ccMixter is one part archive, one part social network of musicians who make their work freely available under a Creative Commons license.