Diaspora is a federated social network released in 2010. It uses a server to server federation protocol, and is compatible with Friendica and Hubzilla.
Users joining Diaspora pick a pod to register their identity with. User identities contain the username, the hostname, and the port if their server does not listen on the default ports. An example username:
Diaspora uses [Webfinger](https://tools.ietf.org/html/rfc7033) to discover users from other pods. User information is returned via hCard, an open microformat standard for identity.
Messages sent between servers are serialized to XML, then signed using the [Salmon Magic Signatures](https://cdn.rawgit.com/salmon-protocol/salmon-protocol/master/draft-panzer-magicsig-01.html) protocol.
Like Mastodon, moderation is done at the server level. When ISIS joined the Diaspora network in 2014 after they were censored by Twitter, all the larger pods moved to block their server.
In this [Github issue about admin reports](https://github.com/diaspora/diaspora/issues/7316), it is possible to see how communities struggle when tools for moderation are not built into federated networks from the start. This user requested a way to forward spam reports to the source pod, as that was the only way to remove content from the entire network. Without this feature, pod administrators resorted to manually searching for and contacting other administrators.
Diaspora posts can be propagated to accounts on [WordPress, Twitter, and Tumblr](https://wiki.diasporafoundation.org/Integrating_other_social_networks).
Diaspora [has not integrated with ActivityPub](https://discourse.diasporafoundation.org/t/lets-talk-about-activitypub/741). A Diaspora developer [reasoned](https://schub.wtf/blog/2018/02/01/activitypub-one-protocol-to-rule-them-all.html) that although ActivityPub tried to make an extensible protocol that could work for everything, it still did not cover some Diaspora use cases. A stricter specification that could be expand definitions as use cases were offered would be better for ensuring interoperability, in his opinion.