I've been trying out Forumbee for the last 2 days and there's basically only one thing I'm really missing and that's points/achievements.
Whenever you're trying to engage people to come back, be an active member of the community and in general helping me out with my product an incentive like this can really help. When you look at platforms like stackoverflow, reddit and technet they all provide something similar.
Looking at the practical part you can start off simple with points being given for posts, likes on your post and amount of followers. It would be nice to give these "points" a name. For example coins, points whatever makes sense to the admin of the community to personalize the thing. Achievements are another nice to have, but that can be further along the road.