I thought it was worthwhile to share my take on this with a bigger audience since I see this question alot, and because I have some experience. I actually started with no knowledge of these things really (much like most things I have done well with...) , and learned this along the way... So rather than type a bunch , I will just share with you my answer to him, and it will help some, if you want advice from a forum owner who's forum produces income:
Give a free report on your subject matter to `1000 people, and hold a mastermind discussion on the subject at your forum, where readers can come participate and you will have a few hundred people creating activity within a short time frame. Keep doing it. Mine first had a hundred members, then I celebrated when it hit 500, then I "SWORE" it would have two thousand by the end of the first year, and then I swore it would double, and two years later it has....but even with more members its less active, and there are reasons.
Stay active on your forum until it hits 10k members or so or activity will die down. You have to work hard to have a good forum.Even when you have 2000 members, the only active ones will be the ones who are active at the time, and that changes in cycles, so until you hit a certain mass, activity doesnt necessarily increase with memberships.
Also, there is NEVER going to be a time when all members are active at once, so if you dream "Im going to get it to 5k members and then start charging monthly- Quit dreaming, because the time you get to that number, you are only going to be able to reach the currently active ones with your message.
Here is the biggest key:
"YOU" being present to help people in real time, is the only difference between your forum and a million others.
Forums are definitely not automated success, you have to be present offering valuable help like a soup kitchen every day, it may be a labor of love for awhile but it eventually pays off.
UNLESS, you stop being active before you hit critical mass, up to that point it only pays if you are working it hard every day.
My forum made 100k its first year because I was working on it balls to the wall 24/7 answering each question practically in real time. I had made it into a real time help center...and it only did about 60k its second year, because my activity there slowed down.
When you arent on your forum regularly, the members feel betrayed, and you lose loyalty from your members, however if you are ON IT like white on rice all the time, they see your dedication to them and they support your causes.
However, depnding on your standards of living, making 75-100k in a year for running a realtime online help center isnt bad. You just have to be available at all times to answer, none of this clocking out at 5pm stuff.
Ps. The way NOT to make it work is to start a thread at the warrior forum asking for help starting a forum, any member that joins on such a solicitation will know that you dont have very good control over what you are doing. Thats why spam is pointless, it just lets real marketers know that you dont know what you are doing when you spam.
Try to create a couple of dozen accounts yourself and have those accounts post topics to make the forum look active......
Take my advice above and get some actual authentic activity happening.