Community forum is the place where people can discuss on various topic and can share their knowledge with others. Nowadays I am noticing that many webmasters are getting interest to build community forum but only few of them get success. However, good content and active members are the main source of a successful community forum. But its really hard to get active member for a new community forum. We need to promote our forum to get content and members. I always try my best to advertise my forum on other popular forum and blogs to attract people to join my forum and participate in the discussion. I don't have much budget for promotion. However, how do you promote your forum ? Do you spend much money for promotion ??
I have promoted forums largely by having a main site first (like a news site of some sort, for instance) and then attaching a forum to it as a kind of add-on, rather than making the forum the #1 part of the site. That way, it's easy to create content and rope in users from search engines and social media, and ultimately guide them towards the forum.
From my experience it isn't difficult to get or keep members if you have a forum you are passionate about. The issue with most forum owner these days is that they create a forum that they aren't really passionate about. People can tell whether or not the owner and/or administrator is passionate about their niche. If you have a forum that is a promotion forum but promoting forums isn't really something you're passionate about then you'll slowly lose interest and so will your members. Now in days you can create a forum for virtually anything. Find something you are passionate about and I can almost guarantee that you will have a successful forum because you'll constantly want to be learning about the subject and you'll also want to be active in your community and want to reply to the threads cause you'll honestly find them interesting.
The only money I spend on advertising is the amount it costs to print business cards. Owning your own forum is very much like having a business so you should get business cards for your forum so you can give the cards out to people who share the same interest in the subject as you. Go around your town or city to see if you can leave your business cards at appropriate places. For example, if you have a forum about gaming visit local gaming stores to see if they will allow you to keep some of your business cards there.
You can advertise your forum on your social media for free as well as you can create YouTube videos pertaining to your interests.
Advertising doesn't have to be costly, though if you really want to make your forum known and popular you may have to pay for business cards and promoters (if you don't have the time to do it yourself)