### Other Federated Social Network Protocols

- **Diaspora**
    - An early decentralized social network.
    - Uses the "Diaspora federation protocol" for connecting different instances (pods).
    - Focuses on privacy and user data control.
- **OStatus**
    - An older federation protocol used by platforms like GNU social.
    - Includes technologies like WebSub and Salmon for federated communication.
    - Predates ActivityPub but is still in use in some networks.
- **Matrix**
    - Designed for secure, decentralized communication (instant messaging, VoIP, video calls).
    - Uses an open standard for real-time communication.
    - Extendable for social networking but not ideal.
- **XMPP (Extensible Messaging and Presence Protocol)**
    - A protocol primarily for instant messaging and presence information.
    - Extended for social networking through various extensions.
    - Known for its flexibility and adoption in various messaging services.
    - Rather complicated and somewhat outdated
- **Secure Scuttlebutt (SSB)**
    - A decentralized communication platform for social networking.
    - Uses a peer-to-peer network, connecting users directly with friends.
    - Operates over a distributed mesh network rather than traditional servers.
- **Hubzilla**
    - Emphasizes decentralized identity, file storage, and cross-platform communication.
    - Supports multiple protocols, including its own (Zot) and ActivityPub.

Each protocol presents unique features and focuses, from privacy-centric networks to broader social communication platforms. They share the common goal of offering alternatives to centralized social media, emphasizing user control, privacy, and choice.