Have you ever joined a forum post a reasonable question (inline with the general topic) but never receive an answer. Do you go back or think this forum is useless? Many guys constantly ask how to get members and keep them, are you guilty of the above, people generally want answers, we join forum mostly because we are seeking something, socializing with other members comes later. It's more likely the bigger the forum the greater the chance of getting replies, if you're starting out RESPOND to all post, DON"T ignore the member. I visited some of the forums owned by people here asking how to gain more member, when I take a look at their forums, I see many just don't answer people, AND YOU WONDER WHY you forum is failing. If you can't even do the most simplest of things, don't waste your time or better still our time asking how to attract more members. If you don't return to a forum you joined simple because you've been ignored, expect your members to do the same.
truer words have never been spoken. If you're not prepared to devote a large chunk of your time, don't bother starting.
Have you ever left a forum because one asshole is just being an asshole? Sometimes you may have a member who decides to be a bully, this guy will eventually drive away your members, problem is he hasn't quite stepped over the line to ban him, he comes across condescending enough for some people to leave. Here is the problem, he answers everything that is posted not always bad but predominantly it is, your forum looks active but notice most members post once or twice never to return. Question would you keep this member or delete his account? Sometimes we have to make tough decisions, if you're not prepared to make hard choices forget running a forum.
I agree, if the admin doesn't have spare time to devote to the forum then there is no need of starting a forum it will be a waste