Help:Contents - Referata
www.referata.com/wiki/Help:Contents
From the page
Saved with the link. Notes from 2007 to 2016 are mostly the page's own words, so this is probably an excerpt.
Referata is a host for semantic wikis; those are wikis that contain data, and not just text - data that can be queried, aggregated, mapped, exported, etc. In other words, you can think of a semantic wiki as a collaborative database.