I'm mod of a medium sized group (10k+), and not because i wanted it. I simply asked the mods why someone was being ignored, so they made me one...i don't go back with enough frequency to handle all situations, but as everyone else is asleep at the wheel, I've done what i can to make sure the group doesn't get bombarded with crap posts.
It is very thankless, but i do think it's neat what tools reddit tried to give us.
Just my .02