By fediverse first, I mean that the app/site/platform was built from the start to be federated instead of being like corporate site but FOSS & federated.
In some respects it feels like many federated platforms have approached things backwards, trying to rework a centralized structure to be distributed/decentralized, creating some of the awkward UX folks experience.
Email, usenet, IRC. Don’t know any of the ActivityPub sites that isn’t based on an existing commercial product.