Forums tend to be very good at attracting SEO traffic, in particular they get lots of longtail traffic, because the phrases by posters tend to be what customers may search one. I would just make sure you have a strong signature and use meaningful titles in any threads you start.
Why I need to do this? It is convenient for users to work with good known layout. May be I'll change skin something later. It will create it's look more unique.
MAKE IT DO FOLLOW AND ALLOW SIGS. aLSO MARKET IT IN OTHER FORUMS TO BUILD UP YOUR READER BASE. mAYBE MAKE A LIST OF DO FOLLOW FORUMS AND INCLUDE YOURS. tHEN SHARE THIS WITH THE FORUMS. tHAT WILL GET TONS OF PEOPLE SIGNING UP