MortiS-the-Lost wrote
The Members Tab on ‘People’
What’s it for?
The "Members" tab is displayed when you define some role to members in the "Who can view & post?" configuration screen. For example, you have selected "Registered users can participate, but restricted topics" (i.e., only members can create new topics in your parent forum). So this is why you have a "Members" tab in the people page (those users can create new topics in your parent forum). I believe you shouldn't have so many members in the parent forum because you should force them to post in sub-forums, but this is up to you.
MortiS-the-Lost wrote
Can I / How do I make people Members?
The option is in the "Options > Users > Who can view & post?" screen.
MortiS-the-Lost wrote
And while I’m at it, why am I the only Admin on my forum that appears in the admin tab?
There are two administrators, see:
http://n2.nabble.com/forum/People.jtp?forum=664610&filter=adminsYou can select who is an administrator in the "Who are members?" screen.