It's working quite well right now.
I think you understand the basics about the forum table.
If a forum is a category, the row is the value 1, if it's a simple forum it's a 0. If it's a regular forum, the "parent" row is set with the forum_id of the category forum that it's supposed to be under.
The thread table is quite easy aswell.
My question concerns the POSTS in the threads.
Should I store them inside the thread table(?? :S), or should I create a seperate table for the posts, like this?