The design of most online community sites is terrible.
Aesthetics is put before function. It's not clear to visitor's what's new in the community. You're not sure what's popular at any given moment. The best communities show this information, and they show it well.
I recommend a simple community design. A basic wireframe might look similar to the design below:
There are other variations here. The key point is every visitor can see, in a heartbeat, what's new and popular in your community.