My site has been up a month and we have about 19 users.
So far, I've sent email invites out to all my friends who i thought may be interested in the subject at hand for the website/forums...and then asked them to forward the invite to any other people they might think would be interested. That did help gaining some members, but no one has signed up recently. Also, i need to mention, that i had a group of like 5 friends go on there and start conversations and make some posts before we sent out the invites...I think that helped, as other's mentioned, to make sure you get the convo's going first, otherwise no one wants to come to a dead forum.
My girlfriend had a great idea to have a "Question of the Week" on the site in order to a) start more conversations and b) to encourage users to come back to the site regardless regularly.
I've been tempted to create fake accounts to have some fire starter type people like "Grumpy" (which is a hilarious and fitting name from your description by the way), but i'm also concerned that I will lose the respect of the other members. ONe of the forum rules is that user's can't create multiple accounts, so for now, i want to do my best to follow that as well....but having a 5 way person conversation with myself could be a lot of fun!
You guys have given me some real good ideas of how to get more members, so thanks, i really do appreciate it. I think i'm gonna try a few out (visit more forums related to the topic of my site and participate but w/o spamming).
An idea that one of my friends had was to email/phone some college campus clubs who are religiously affiliated (the site is for people who wanna to talk, listen, and learn from others about beliefs or non-beliefs systems), let them know about the site, our intentions, and see if they'd be interested in passing it on to their members or plugging it in one of their next meetings. I also was thinking of maybe printing out simple business cards and dropping them in stalls and such, with just a link. Then again, i'm not sure who'd want to touch something laying on a toilet.
The great thing is that i'm not trying to sell anything, as far as making money goes, and my intent is to allow people a safe place to come and talk about tough topics. So i think i have an advantage because they know i'm genuine and not just trying to solicit traffic for the sake of making any $$$.
One last note...its funny cause some of my friends i've told about the site, they get really pumped on it, and want to go invite others, such as college professors, but then they haven't done anything so far. I guess that's the difference between talking about doing something and actually doing it!