Little to nothing and we are payed accordingly, just kidding. Many of the moderators would normally be spending time at the forum they just include in the day the duties of monitoring different threads to maintain a certain quality of civility and take part in the dicision making of future additions and/or changes to improve the quality of the forum in general. I have been away for a month due to an accident, that is higly unsual but if you are to be a moderator you must be present a reasonable amount of the time. I do hope this helps but perhaps another mderator will put his/her two cents in for futher clarification.
Yeah, we just spend some free time here, enjoying the conversations. When we see something awry, we try to correct the problem. Delete spam, move misplaced threads, try to soothe the occasional bit of nastiness.