From my previous experience with an US based Insurance community site, I can share some of the points as to how you can manage an online Forum or what is famous as Online Community or Discussion Forum. The forum I worked for, was an Insurance forum as well as a community, which was made to sort out the problems of the US insurance consumers (what they face in their daily life with respect to the Insurance policies).
I had to do the works in the supervision of my immediate boss Mr. L. Phukan, a diversified knowledgeable person and a good guide as well. From the scratch we had to develop the website to an Insurance Forum which will be recognized worldwide. That was our approach.
We started doing research taking along the technical team that what should we do so that each insurance, each country, every insurance consumer could be incorporated. If you move to the site, you can realize the fact.
How did we start the Community Building – You can follow that:
1. Keep on posting the pseudo posts regularly (every day) to each forum.
2. Carry on the posts in a discussion manner.
3. Try to maintain the language construction and spelling mistakes.
4. At the same time do some organic marketing.
5. Use avatars.
6. Build different characteristics according to those avatars. (Ex: If you use an avatar of a DJ, the write ups should reflect that character).
7. The above part helps to build an imaginative character in the mind of the visitors. That in turn serves a psychological purpose of web usability.
8. While making posts to the forum, create 8 to 10 identity on your own. And use avatars for those.
9. Try to include other resources, design from time to time.