I'm from the United States of America.
I play on the international version, the US and UK versions, the Canadian version, the Australian version, and I also play a bit on Equideow (the French version).
I suppose this one has two answers. Here, on the US version, I have been a moderator since July 23, 2012. Before that, though, I moderated on the international version for bit, so in total since May 31, 2010.
Those are the same administrators that are here, actually. As for the question, the administrator who sent me the invitation to join the moderation team has since stepped down, so none of those. It was a combination of SarahKat and Ow that switched me from moderating on the international server to moderating on the US server, though it was at my request.
The international server is running fine; I'm not sure I understand your second question here.
I enjoying being able to help players with things they are having trouble with; in particular, I enjoy seeing that metaphorical light bulb click on when a player understands something or has figured out how to do something that previously stumped them.
The more unfortunate side of moderating is when players decide not to follow the rules; I don't particularly enjoy sanctioning players, and it is also disappointing.
I'm sorry, I'm having trouble understanding what you are looking for in this question; perhaps you could rephrase it?