Smallest Federated Wiki was invented by Ward Cunningham in 2011 as a continuation of his life's work in computational poetics. Or was that consulting? Ward is best known for having pioneered the original wiki engine upon which the world's encyclopedia turns. Federated Wiki could thus be looked at a decentralization of decentralized collaboration in that each page stores a history of its movement through the federation in lieu of a centralized versioning system.
Ward Cunningham started the federation in 2011 with a workshop project called Smallest Federated Wiki or simply SFW. Early history has been documented in a series of video screencasts. Search for "video".
A community of open-source developers maintain both the client-side and server-side applications most frequently used to browse and edit pages. Pages themselves are composed of paragraph-sized items of various kinds. This same community provides a core set of plugins for rich content pages and a variety of experimental plugins that push boundaries of web computing. github 
We publish federated wiki software as a Node.js package ready to run on a variety of platforms. This is usefully run on a personal laptop or an industrial server in the cloud. Most people get started by joining a community and launching sites and/or servers with their help. The server software supports a multi-tenant "farm" option useful for small groups or heavy users. npm