Reservation & Ref Reservation - An Explanation (Attempt)

So in this article I'm going to try to explain and answer a lot of the questions I get and misconceptions I see in terms of ZFS and space utilization of a pool. Not sure how well I'm going to do here, I've never found a holy grail way of explaining these that everyone understands - seems like one way works with one person, and a different way is necessary for the next guy, but let's give it a shot.