Content Panes are areas of a page where content Modules may be placed. Each page can contain an unlimited amount of panes and the panes may be placed anywhere on the page. Although panes are always present the outline of a pane can only be seen (Figure 1) when a user is logged in, has permission to edit the page, and has turned on Layout mode (top left hand corner of page).
Each content pane can contain 1 or more Modules. If a module is not placed in a pane then the pane will not be displayed when the page is viewed and the panes that do have modules in them will grow to take up the space not being used by the empty pane. This allows skins to be created that can support various layouts. For instance, referring to the below image if modules are placed in the pane labeled ContentPane and RightPane is empty then essentially the page will be viewed as having one column. If modules are placed in both panes then the page will be dispalyed as a 2 column page.