thats a realy good question for that i have no idee :/
i also have a "new" forum
www.developer-network.orgi'm trying to "post" it everywhere, but 1 month later=> no people

i don't know what to do
Few suggestions.
1. Start a General Chit Chat Board
Make it a no post count board.
Get activity, get people so they aren't scared to post, and soon they will post in teh other areas too, thats the whole idea.
2. Challenge yourself to make at least 5 post a day yourself.
Never fully close the post, leave it open ended so they have to ask questions to get the rest of the story or information.
3. Make sure to reply to every post personally with in 12 hours or less. The sooner the better, No one likes to wait for information and they will go looking somewhere else very soon. The internet has us accustomed to instant gratification and instant answers. Use your best judgement, if they are online or if you catch it with in 2--5 mins after teh post, then ask questions, to get more information on their problem before offering a solution or suggestion.
If you know they are online, maybe leave the post opened so they have to ask you a few questions to clarify your answer.
Everything adds to more post which equals more content, which is what brings people to a forum.
I just started my first one on Dec 23rd
less than 2 months
We have 129 registered members.
Our users have made 14164 Posts within 755 Topics.
My forum is mainly just entertainment........ lots of info to be found too, but the majority of it is simply killing time at work, or boredom and simple entertainment value. Thats it!
I've had the hardest time figuring out how to market it, like to swap links with anyone, because there really isn't a niche for it. No company or site in particular to target to swap links with. I've just grown so far form word of mouth and surfers.