I have just created a private area in which only members and see and post.
The Private Plane is an area which you go to if you have a problem but would rather that nobody else apart from the admins can see. Which means, you cannot read or see other people's posts. This is why it's called "Private Plane"
You must not use that area to make spam posts, spamming is banned from all areas of the forum, except for the Spam Box, the only spamming area in the forum.