Let me "step forward" and volunteer to candidate for the role of a moderator in the service of the MathOverflow community. This is certainly not to claim that I am the best one to take this role, and I also suggest you to take my candidacy as an encouragement to candidate yourself.
First of all, I would like to emphasize that the present moderators have done a great job so far! --
In fact, I cannot remember to have seen a single instance where I would have disagreed with what a moderator did or did not do. I would feel honored to get the opportunity to help that also in the future as many as possible members of the MO community make a similar experience.
From a practical perspective, while 54 of the 6 present moderators are based in the US and, one in Japan and one in Australia, I live in Germany and and would thus improve the the coverage of time zones in Europe.
Finally, getting back to what I said above, in due course I will nominate at 2013 Moderator Nominations someone else whom I think would be an excellent moderator.