on vizsla forum that I moderate we don't have a tiered structure so to speak, (apart from staff), yes we have tags, but that's just awarded on post count than merit, but tbh it works quite well and although we only have maybe 6k members it's a breeze to moderate as everything is on view. Calum, who owns the site probably only logs on once a week, and myself and a lady called Mary do the day to day stuff. I know it's kind of a different scenario ie, dogs = hobby, tiling = income, but I think the less tiered structure takes away peoples apprehensions about posting against a more "ranked" member. Just a thought.