Mastodon
self-hosted, social networks and forums

Mastodon is a federated microblogging server designed to provide users with a decentralized social networking experience. It allows individuals, communities, and organizations to set up their own instances, each with its own rules and moderation policies. Users can interact with each other across different instances, follow accounts of interest, share posts, and engage in conversations. Mastodon emphasizes user privacy and control, offering features like content warnings, customizable timelines, and robust moderation tools.