Reputation

Is the reputation of the sites admin important to you and will you only join a site that's admin is well know and respected?

Partically yes. The admin makes you decide if the forum is reliable.

Yet how is an admin suppose to get rep if they are starting out?

If they start doing services for a new promotion forum (I find) users usually thank them...
I've done every single service on this forum so far, and I have 14 reputation.

I think it is important because members need to respect an admin or their site becomes a play room.

Well, it is not always possible I'd know the admin before I join but it helps to have an idea what to expect is several aspects of the community, as well as being in itself a great incentive when we refer to positive reputation.

Personally I like reading around to get a sense of the staff by checking the rules, announcements, etc. they way they word their threads has been decisive for me to register or just close the window.