forums are time consuming – my best advice is to close the forum and make some good usefull content instead. Don’t go to war if you don’t have a chance of winning. The big gambling forums are way ahead of you.
A forum with no posts is really not the best way to make your site appealing to users – if your site have a forum with no posts the general user will think that your entire site sucks and leave.
If you really must have a forum – don’t start out with making 30 different forum catagories – start with one or two forum catagories….
If these two catagories at one point starts getting too many posts for the new topics to stay on the first page – then make a new catagory.
That is how the big forums grow I am sure.
To start a succesfull forum think of ways to diversify yourself from other forums – what do your forum have to offer that can not be found on 1000 other forums?
On my former site we had a very very sucessfull forum – sure it adds stickiness to a site and also generates a lot of free usefull content. However running a forum is so much work that I will not do it ever again.
Good luck