Being a mod can be very rewarding. I wouldn't call it fun though. You're basically spending a lot of time every day with a bunch of people from all over the world who share a common interest, and you can make a lot of great friends, and learn more than you ever wanted to know about whatever the forum's focus is. But it can also suck the life out of you, leaving you a jaded husk of the person you were before you joined, heh. Especially on forums that are more strict, like the one where I've spent most of my time. Enforcing all those rules can be draining, and you end up dealing with a lot of angry PMs from people who break them. Which can be perversely amusing, but more often than not it's tiresome.
I've been on a nearly year-long break from my mod position on another game site, while I focus on getting my degree, and if there's one thing I remember from those other forums is that the people who were the most eager to be mods tended to be the worst candidates. Maybe that observation is unique to the forums I mod, and here it will be different, I dunno. I wish good luck to all who applied in any case.