There is only one problem with forums... activity. It is hard to be active. That is rather problematic. School, work, etc. all contribute to this inactivity. Sometimes, there is nothing that you want to say... so, yeah. that's the problem with forums. What is the solution? Welp, I honestly don't know. Although, it could just be to simply post random things! Huzzah!
Persistence is definitely key. Keep posting, even if no one replies. No one wants to be greeted by an empty board. I've seen far too many forums out there, many young and struggling, and sadly many look as though they could be interesting. They could have great potential, but far too often, after several months, maybe weeks, or even merely days, the forum is already abandoned.
Yah. It is hard for me especially. Running a forum is surprisingly hard, and must be done correctly. I realized that with my older forums. They can't succeed if I don't stay active. From now on, I'm going to make an effort to spend at least 10 minutes per day on the forum, unless I'm traveling.