Small communities like this die at the hands of site expenses and members growing up and getting on with life.
My take on expanding and bringing in new members is you need to offer something, be it reviews, videos, or free swag. None of that can be accomplished with just a forum alone, so that means branching out and making a front page.
Otherwise the forum will continue to operate as is - like a small community, an enhanced version of IRC or AIM - as long as people are willing to keep up with server costs.
Alternatively, we could offer porn. Porn brings in traffic.
