The Origin is the site from which we started browsing the federated wiki within a given browser tab. The origin is first among equals, wielding some unexpected power over our experience.
The origin determines what plugins will be available for interpreting cards 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 cards 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 cards stored there.