Are you sure it's your forums that are at fault?
I mean no disrespect but the first view as a guest is a bunny repeating background. Personally, that's an instant red flag for me to disappear. I see you have a bunch of other skins available. But as a guest, your first seconds are crucial in gaining a member or the fact that they bounce.
Furthermore, free hosted forums do have a harder time gaining traction. This is mainly because we are all very busy with real life and often prefer more established / premium forums. I've written a blog piece about this a while ago. This
might be interesting for you:
Struggling to gain traction with your free hosted forum? Discover the benefits of upgrading to paid forum software such as Invision Community, Xenforo and Woltlab. Engage your community like never before!
freeforumhosting.com
For me personally, I pay less attention to free hosted forums when I'm browsing the internet. While I have ran countless free hosted forums for over 15 years.
Maybe that's just me though.
We're here to help anyway, so if you have any concerns, post them.
But as with anything: Content is
King.