Well if you're going to do so get a good domain, hosting, etc, etc, etc. Plus my suggestion, well not even suggestion my personal favorite type of forum is IPB. Try it if you want, it has more vulnerabilities I won't deny that. The overall look is just more appealing to myself. In before mybb fgt.
My thoughts on making this type of forum are that it wouldn't succeed; simply because it's already been created. http://yttalk.com/ - You could always give it a shot, but you would need to bring something fresh and unique to the table. Good luck.
That could be an interesting forum, although there are a couple of social-engineering-based forums already out there, such as 'SocialEngineered'. HackForums disallows social-engineering discussions, so having this sort of forum could attract more publicity.