Thank you so much for your interest in our product.
Could you please help us to clarify “private topics”? If you would like to create a topic that only member can review, you can set it by creating a new category that allow member can view only such as “Private”. After that, when you create a new topic, you should choose “Private”. Please kindly take a look at this image http://i.imgur.com/0hDi6qy.png
If you have any other questions, we’d be happy to answer them!