Hello,
I've made an online forum for my game, Fantasy Imperium.

http://fantasyimperium.com/phpBB2/index.php

I was wondering if anyone out there has any ideas for how to promote an online forum?

What are good ways to attract members?

I have had probably 500 ppl download my game, but it's hard to get them to talk about the games.

Just curious to see what has been done by others. :)

Since the forums are specifically for your game, a lot of general advertising techniques won't work very well. You'll basically have to just contact the people who have your game, and hope to attract new ones through your website and the products. So the first thing I'd recommend is to put links to the forums on the site and in anything people can download. If you don't already have an e-mail mailing list, start one.

After that, start by putting an introductions section on the forums to allow people to introduce themselves. Often, people will feel intimidated about posting the first time and this gives them a low-stress way to do it. A fre for all area is also good - let people talk about whatever they want to and they'll stick around more.

Another thing is to emphasize the forums as a central location for support. For myself, when I get questions by e-mail, I'll sometimes post a topic with the e-mail text quoted and my response to it, and then e-mail the person to let them know their answer is on the forums. Then, if they have any followup questions (or any future questions), they'll know to ask there. Additionally, make announcements on the forums, and do surveys to ask about future events and products.

I strongly recommend allowing guest posters - that way, even people who don't want to register can still be expected to use the forums when they want assistance.

I take this even further by requiring illustrators, other freelancers and playtesters to post on the forums (using boards hidden from the general public). This is stuff I could easily do by e-mail, but getting everything over there makes for the appearance of activity, and the appearance of activity generates real activity.

Looking at your forums specifically, I think you have too many topics, with too narrow a focus. I would start by combining:
Combat with Medieval Warfare
Spiritual Warfare with The Church...
Setting with Fantasy Worlds... with Historical... Resources
Story with Adventures

Doing this will make people more likely to read (and commenton) everything - right now, they'd have to do a lot of extra clicking. You might also condense things even further - on my forums, I have a single board devoted to all rules questions/suggestions of every type. (I have only 6 public forums and 3 hidden ones).

I'm sorry that I, personally, can't offer words of wisdom relating to the advertising of forums. My Invader Zim fansite, which receives 500-600 unique visitors each month, never has anybody go into the forums, despite constant plugs in the front page, and a prominently placed "Forums" button.

Sure, we had some chatter for awhile, but it was one dude who was posting with his friends until they got tired of talking to themselves (and me).

So if anybody can help Mark here, I'll be listening eagerly. I can't think of anything, and I've thought a lot.