I've struggled with this problem for a couple years. I've got a vbulletin forum, great domain name, unique topic but I can't seem to get people to join my site and stay. The ones who do join usually just leave after a few days. I even have some active topics to discuss. How can I get users to my site and keep them? I've recently tried adsense but nobody signs up either. Please advise.
Maybe you find something that w'll help you in another reply of mine on the same topic: https://forums.digitalpoint.com/threads/how-to-get-members-to-new-forum.2649067/#post-18538955 You must come with something original to make them stay on your forum. And you should have a team that is made of your friends or trusted people.
You need to get some respected people in your niche to sign up and post. You have to make it worth their while in some way. If you give them a good presentation you can pull it off. Maybe you can offer them free advertising among other things once you get the forum rolling. You will need to clearly explain to them how you plan to advertise and get the momentum for your forum. I hope it becomes successful. Steve