It all really depends I guess.

Some people set up a server and leave it at that, others are programming, others are heavily into the communities and the list goes on.

If I'm not mistaken in my numbers, 8 of the top20 witnesses have a FULL RPC Node running too, which means that part of their earnings are being reinvested back into ensuring we get what we voted for: A reliable Steem blockchain experience!

So, you could say that there is a lot going on behind the scenes, I'm learning the ropes still, young fella!

Man do I love that "Young fella" :)