Well I don't know about advertisement company... But I have a promotion site and I got to say, it's working out very well so far within the first 3 months. I have 65+ members and over 1400+ posts. All that really matters is that your forum is different from others. From design to content, services, easy navigation and everything else successful in a forum. I believe I have done that and it has some success. Remember, dare to be different