I will only speak for myself. I was a very (and by very I mean very very) active member of Serverfault before I became moderator. I literally answered hundreds of questions in the first months.
At the time Jeff asked me if I wanted to become a moderator, I accepted and I somehow felt relieved, because I could help improving the site without writing answers which for me is almost a physical effort (I'm exaggerating of course), because I have to pretend that I
- know something about sysadmin stuff (which I only do to a certain extent; actually in some areas I'm an expert)
- speak English in an acceptable way (you can see in this post that I still struggle)
So, from that moment on I focused on my moderator activities – which by the way was much harder than it is today with all those fancy tools. ;-) I particularly like to improve posts, clean up stuff, remove worthless posts and spam etc. I visit the site every day (between UTC 7 and 18 multiple times) and I try to work on every flag I see (and I'm able to handle).
I admit that I'm not actively contributing Meta SF, though I read every post. But most of the times I have the feeling that other users answer the question there in a much better way that I could do given the time I have to spend on SF and StackExchange. By the way, I like other SE sites too, and recently I actively helped to grow the German SE siteGerman SE site (as Italian, yes!). It's not something that takes much time, because there are only few questions.
Also, I am not not a chatroom-type person. I simply can't make it a habit to have an open window with a synchronous type of (not work-related) communication. Though I absolutely understand that a moderator should be there (at least regularly).
I am the last person in the world who clings to his SF-job and I told Jeff when I started that he (or other people in charge) could tell me if something was not okay. So, whoever thinks it's a good idea to bring in fresh meat (is that a phrase in English? Who cares.) – I'll be perfectly fine with it. Maybe I'll give more answers. ;-)