TreeMode pages mainly consist of links to other pages. They should have some text at the beginning to describe what they are for. You will often see TreeMode used for SubProject pages, like DebianJr. It is usually good practice to not edit these too much, since they are most often maintained by one or two clearly identified individuals. FrontPage is also an example of TreeMode.
Elements of good WikiStyle for TreeMode pages
The RuleOfSeven suggests that you shouldn't have more than 7 major links in your tree. If you do, maybe you need subtrees.
- Use bulleted lists for your major links, and increase the level
- for sublinks/subsections