To give some very general advice: I think you need a much more user-friendly interface than kareha. Sure, it's very easy to use for us experienced users, but you need to think from the point of view of a stupid 40-year-old who is new to the Internet and has a very short attention span. They will not be able to figure out how to post a new thread or reply to threads without someone pointing out how to do this. Unfortunately, I can't give any specifics on how to make this easier except maybe make the reply button big and obvious. Also, the thread view should look clean and easy to read, maybe more in the style of PHPBB where each thread gets its own line, instead of having all the topic titles run together.

Hope this helped a little bit.