Well, my experience about forums is that it is extremely difficult to bring them to life.
See the newsgroups nl.sports.dammen or alt.games.draughts or even the forum of Damweb (which used to be frequented a lot but not any more these days)...
The first forum of my site was not very efficient either. However, after some polemics (!!) suddenly this year, the second version of it started getting attention in France. Now, it is possible to say that there is at least one lively forum talking about our game :
I still find it a miracle !
As written above, I consider it very tough to bring a forum to life. The reason is that it is like a fire : you need a lot of effort to get the first spark and then a lot of effort to change this spark into a real fire. You need to attract a critical number of players (30-40) that will regularly post and read. And when the fire is there, you need to be very cautious in order to avoid any loss of traffic. The fire needs to be feeded on a very regular basis. Otherwise, people stop getting answers to their questions and quickly lose interest. Your forum is dead.
I wish you a lot of success though, because the FMJD site is the ideal place to attract a lot of players.
Be aware though that you need to make a lot of publicity if you really want to have a chance of getting a lively forum.
As far as your questions are concerned, I would not have different categories as long as the forum is not really lively. There is no need for it right now.
And as this is the official forum of the FMJD, I would tend to think that some day, sooner or later, you will have to moderate it in order to avoid messages that would harm the image of our beautiful game.
PS : find a good polemical subject and your fire might arise ! [img]http://laatste.info/bb3/images/smilies/icon_surprised.gif[/img]