[aceofspades]

The best way of explaining it is this forum (or at least how it was before they changed the mods page).

The forum page has catagorys :
Cat 1
Cat 2
Cat 3
Cat 4
Cat 5

The mod page has the following catagorys:

Cat 6
Cat 7
Cat 8
Cat 9
Cat 10

So in effect it looks like there are two different forums, because on each page (mods and forums) there are totally different catagorys containing totally different forums within the catagorys. However it is just one piece of software, just using conditionals to hide the catagorys from view on each page only showing the catagorys related to that page, i.e Cat1 for the forum page.