Just wanted to give some advice on how to get your forum going... (new members, more posts, and etc)
1) Create about 10 fake profiles and start talking to yourself (using great content and titles). Yeah it sounds weird, but no one will join your forum if it's not active at all. Do this for a couple of weeks so your Discussions can be more than 10 for each category that you made. Let's be honest, if you see anything less than 10 discussions pet category on a different forum, your leaving right?! Well it's the same for your forum and your guests visiting.
2) The best way to get traffic in the beginning in my opinion is youtube. Do a few videos on your site and it's related content and post it. Make sure to include your website url underneath (in the description) and mention it in the video. Tell the viewers to come by and if they need any help, to just post on the forums. I have seen some of my youtube videos be ranked number 1 on a google search before my SEO content on my website that is realted to that video.. so just know, youtube is very powerful.
3) Content.... This is very important. A forum with lot's of content is just determined to succeed. People come to sites to learn about stuff. This will be either through your forums or your content. But since your forum will be weak at this point, your content needs to be strong. And make sure you keep updating your content. Make new posts weekly. Let them know new posts will be here next week and the week after, so they can keep coming back next week and the week after ad so forth. But don't right BS content. It needs to be GOOD! If people read BS content, expect to never see them again.
4) Offer prizes once you get a few members joining, so they stay and keep posting
5) Join other forums and start answering questions... but make sure you have a good signature so people can link to you from your postings. This is how you steal members from other forums.
6) This has been the most effective method (credit to webhostingtalk.com)....
If you have an email list, send out an email and say....
"Free 1 year VIP Membership for anyone who posts 15 messages on our new board."
What this does....
It gets people to post (a lot of people)
It gives people a taste of VIP Membership and will make them want to pay for it later on (if you are running a paid upgrade)
and it gets the community going.
This is just a few tips. I hope it helps.