Original content, forum contest, backlinks, adwords, seo, social bookmarking, article marketing, be active as forum owner, add a blog to your forum, welcome new members, create signature links on other forums, comment blogposts, link exchange, optimize forum titles, add sitemap
Any ideas for a viral marketing technique on vB? For example you can make a contest with real prizes.
Read this thread - http://forums.digitalpoint.com/showthread.php?t=848162 My Youtube and google traffic compared side by side - http://forums.digitalpoint.com/showthread.php?t=850045 I promote my site mostly on video hosting sites such as youtube, dailymotion, metacafe and yahoo video - just to name a few. Even though google refers more people, the people that come from youtube stay longer and are 20% - 30% more likely to register an account. The people that come from youtube also spend about twice the time on my site, as compared to google people. the youtube group also looks at about twice the pages as those that find my forums from google. I found the directory listings a waste of time. Either the listing wanted money for a single link, or it took a week to get my link to get approved. And that was after I already posted a link back to the directory.
Try to improve your search results ranking. You will get lot of traffic from search engines. Do on-page and off-page SEO. Build lots of backlinks.
Depends on the niche. If you want to compete with an existing site, make your forum better. Give it features that aren't on other sites. If it is in a niche where you are the only one, start working on SEO, finding anyone with slight interest, etc. Good luck.