We have global moderator and normal moderator i don't have any title as such as i'm too busy maintaining the back end but we don't have titles like global admin and normal admin as both could delete our forum and or our site.
Global moderator on the forum side has reach over all forums while moderator has reach on only one specific forum.
Admin is probably in the back end fixing the nuts and bolts.
Global Admin only a different name is probably the CEO.
On the editorial side this is a little complex as the roles are different, basically you have the power to publish pages, we only give power to publish pages to people we have screened, contributors may become an extension of forum powers however.
