The Origin is the site from which we started browsing the federated wiki within a given tab. The origin is first among equals wielding some unexpected power over our experience.
The origin determines how browsing works since it provides the javascript for browsing.
The origin determines what plugins will be available for interpreting pages from any site.
The origin controls what mechanism will be used by an owner to login for write access to a site.
The origin keeps and shares pages changed by the owner once that owner logs in.
The origin serves as a key into browser local storage thereby 'owning' in some sense the pages stored there.