A sysop can serve a combination of host, operator, editor, censor, trolling and recruiting functions. It is a composite role often taken on in smaller projects and may be an abused term in some contexts where a narrower role is implied. However it is nowhere near as abused as the nasty "term:administrator".
 at zooid
Anyone may volunteer to manage system services, provided they are known. Since zooid is a small group without any mandate other than keeping defined services running, definition of these terms is not anticipated to be an issue in the near future.