Well a forum is a url like any other.
There is nothing different,content,link building,good on page,domain autorithy.
This.
If you are up against the root domain of the forum it is definitely not going to be as easy as one might think if they are even remotely good at seo.
What? your service?
Get Zombies, DDos it 1 week long and it's gone.
This. = +1