All forums have Categories, categories are used to divide up the forums in which post are stored. Now, if you want to get members to stay in your site more and post more, I suggest adding a Category in which members can chat about things that are not related to the site's topic. Most people have it in their forum already, most people use as the Category name "Members Lounge" but you can play with that depending on the name of your site. In that category you can add a forum called Chatter Box, Speak Your Mind ect... And there they can post anything that is not about the site, if you want to go further you can add a Multimedia forum or a TV forum.
Apart from the Members Lounge category you should always add a category at the top of your forum named "The Site" or the title of your site like "Forum Blog" and in that category add Announcements, where the site staff can post announcements regarding the site. Also add a forum called Suggestions where the members can post their suggestions on the site. If you don't have a forum called "Introduce Yourself" where members can introduce themselves (the title says it all... LOL)
If your forum has a lot of members and you have many staff members, as in Moderators then I do suggest a "Staff Hub" or a "Staff Forum" where only that admins and moderators can see that forum, and this can be made by playing around with the Permissions
Just a little tip for the newbies :D