Being a server admin is less the role of leader and more the role of .... well hes the cool guy that pays the bills and you hang out with.
Normally, the admin wears a LOT of hats. Most of the time, he is a cool guy that is off doing something. Sometimes, he has to put on the cop hat and banhammer someone who has stepped out of line (the internet makes it too easy to disassociate human reactions, sadly). Other times, the teacher/troubleshooter hat to assist people with stuff (because it is his server, so he's the one that has to help even if it is to tell them to look in NEI for the billionth time).
And, sometimes, yes: Leader. But that is rare, and non-existent when you have no members.