A forum doesn't get real active by telling people in your direct area, trust me.
This is by all means the worst time for the activity of forums, ever.
I've never seen so many unactive forums, so many forums simply dieing...

In normal times, forums would become active by just mouth to mouth advertising (e.g. classmates talking to eachother about it), but as I said, these are not normal times.

To my opinion, populairity can be gained by paying.
Google Adsense had a unique system, which will display ads where appropriate.
On a Diablo II forum, it will show Diablo II advertisements.(just an example)

This is, to my opinion, the best way to get new members, in times like these.

Getting a new permanent Admin wouldn't fix it, but what about a temporary one?
An Admin whom is still a teenages, with priorities set differently.
I'm sure there are atleast 5 (including me) expierenced vBulletin Admins, who would love to help out installing a hack or 2.(even coding one)

I have recently been doing a job for a friend at his forum, which -if done by pro's- would normally cost him over 200$(no kidding), and I did it for free.
I'm sure there are more people here who would love to do things like that for this forum, completely free.

It's a shame the sup. mods don't know anything about vBulletin hacks, else you could maybe make them an Admin(you trust them, right?).

What would be the bad thing about making a teenager, who has different priorities, an admin?

Even though making changes might not be a nice thing when you do it, its always nice when you can look back and say "Pfff, I'm glad we did that a year ago, else this forum would've probably been dead!", isn't it?
I'm one of this people who hates changes, really.
But sometimes changes are needed, and you have no other choice...