One of the things I've seen more than a few times is a failure to gain critical momentum. I have an untested hypothesis that this is due to attempting to start

One of the things I've seen more than a few times is a failure to gain critical momentum. I have an untested hypothesis that this is due to attempting to start with multiple forums rather than a single 'general' forum. It's my belief that forcing this choice, and not providing a single page showing what's new in the forum lessens the likelihood of engagement with your users. Once your community gathers momentum, it should be easy to add new forums as 'general' starts getting busy. Having a problem with scaling is a good problem to have ;)