Rotonde was a decentralized social network.
It is a commonly agreed upon specifications of a JSON object shared between members of the network, its current incarnation is the webring's Hallway.
Nobody owns the network, it never goes offline, there are no servers and no central authority. All content is editable, versionable, hosted on your own computer and seeded by anyone who wish to follow your portal.
Last update on 17Y08, edited 20 times.