Personally i don't think it matters to much especially if the moderators are very involved and do a good job. As long as there is someone to help members out when need be then thats fine. I am the administrator at a pet forum
( << url snipped to comply with forum policy >> ) and because we have not been up long we only have around 55 members meaning i am as you call it the "glue" that holds the community together. I don't think there would be much of a forum at all if i didn't join in lol. Anyway all in all i think if you have many members and good moderators it's not to important and it looks to me as if these forums are doing very well.

I think if a community is developed around an individual's personality, it is critical that person continues to participate. This has been said before by others, and there are plenty of examples out there.

There is nothing in the "book" that says you cannot change the personality of a site, over time to remove or distance yourself. Or you can do a cataclysmic change, with big fanfare, and create and announce a super-moderator. Both works, but both require very good finesse.

This is why my business site that I am trying to bring up (discussed in other thread), will NOT include me, but start with moderators immediately.

I think after a forum gets more then ~100 members that post regerly the moderaters should be incharge of answering the questions and the administrators should do the behind the sences stuff and only answer a few questions.

As I'm sure you now can guess, I'm definitely always making changes. Amazingly the design we had lasted for a year and a half before I decided go undertake this redo. But alas, here it is! (Still tweaking things though).

Our current system is the following ...

administrator = me = code the backend of the site, design / tweak the frontend of the site, add new features (and code them, for that matter!), do all of the marketing and business relations, sell advertising, etc.

super moderators = oversee everything, daily forum maintenance, handle community issues that may arise, moderate incorrectly placed, spammy, or otherwise problematic threads and posts

moderators = assigned to specific forums to act as community leaders among their forum, reply to threads answering questions within their forum, ensure all questions within their forum eventually go answered, lead up the group of regular members within their forum, strengthen the mini-community that develops within their forum

Admins should be very involved, I take as big part in my community as possible, and thats the reason for its success now I believe.

Well, as admins, we'd all love to take as big a part in the community as we can. If I had enough time to answer all of the technical support questions, and if DaniWeb were a better place for doing so, I wouldn't hesitate. But the matter of fact probem is that the bigger a site grows, the more behind the scenes things there are to take care of. And sometimes there just aren't 48 hours in a day!

And to balance all that you do with school must take an awful load of time

I think it depends on who your second in command is. If you've got a head moderator who can function independently on your behalf, then an administrator does not have to be that hands on. But, I think the forum members have to feel as if someone is steering the ship, and I'm not sure they're that concerned with who the helmsman is, as long as the site is functioning well.