actively edit and maintain a whole encyclopedia What about just maintaining a set of annotations (highlighted passages, sidebars, extra references, etc)? Wiki

actively edit and maintain a whole encyclopedia What about just maintaining a set of annotations (highlighted passages, sidebars, extra references, etc)? Wikipedia would remain Wikipedia, and your overlay-pedia (?) would be a wrapper. Major edits to a heavily annotated page could trigger a notification to someone who could then try to update the annotations.