Mastodon

Mastodon is a self-hostable social networking server that lets communities run their own microblogging platform while participating in a broader federated network. It implements the ActivityPub standard so users on different servers can follow, reply, and interact across instances.

Key Features

• ActivityPub federation for cross-instance follows, replies, boosts, and content delivery
• Rich posting features: content warnings, polls, media attachments, custom emoji, and hashtags
• Multiple timelines (home, local, federated) plus lists and search/discovery features
• Moderation and safety tooling: reporting, domain blocks, account-level actions, and role-based admin controls
• Media handling via background processing, previews, and configurable limits/retention
• APIs for clients and integrations (widely supported by third-party mobile/desktop apps)
• Theming/branding and instance configuration for community-specific rules and identity

Use Cases

• Run a community-owned social network for an organization, group, or region
• Create a moderated public microblogging instance with federation to the wider Fediverse
• Deploy a private/internal social feed (optionally limited federation) for teams or associations

Limitations and Considerations

• Requires ongoing moderation and operational work (abuse handling, federation policy, and resource planning)
• Search and discovery are constrained compared to some centralized networks due to federation/privacy trade-offs

Mastodon is widely deployed and integrates with a broad ecosystem of clients and Fediverse services. It is a strong choice when you want a familiar microblogging experience while keeping control of policies, data, and community governance.