[goddess_dix]

you're best off with a topic you're interested in. you spend lots of time surrounded by it when running the board, you'll end up learning a lot about it, and you'll do a better job of managing your board if you're knowledgable about the topic at hand.

i wouldn't even bother with a "general chat" board because there is absolutely no reason for anyone to register for something they can go two million and two places on the internet for, often without registering squat. people register for forums because they find them interesting or useful. unfocused discussions are usually neither. think about when you register for a forum, and why. when you want to ask a question? when you're interested in learning more or discussing a particular topic, right? not just to chit-chat, most likely.

not to mention if you hope to make money with the board, you need a sense of community. a random traveller may or may not shop in your store, but a member who likes the community and wants an easy way to support the site will often do so if you make it easy for them, and feel good about it in the process.

in order for this to happen, your subject needs to be something they care about, enough to sign up to begin with, enough to particpate, and enough to want to support what you're doing.

add supplimental content, at times perhaps driven by the needs and issues you see taking shape on the forums, and you've got another way for prospective members to find you plus you're serving the community at large.

in a way, i think you have the questions kinda backwards. find a way to serve a community, and the members will come. make the topic related to something you personally feel some passion for, and you won't regret the hours you spend working on the site. plus, chances are you'll have a much better site because your personal interest in the topic will help guide you in your decisions.

and as far as the time commitment...well, yeah, there is a time commitment. but it's not reasonable to expect to have this big board you want to run just take care of itself. you expect it to make money for you, so you have to keep things running smoothly, add content, manage memebers, upgrade software, add features, blah blah blah. there is no free lunch.