Tree-Style Documents

A typical document is structured heierarchically, with a main body, sections, sub-sections, footnotes, and so on--like a "tree," with a root, some branches, and many leaves. Yet we don't read it that way on the Web; instead, we typically read documents either as one big long page with numbered subsections, or as a collection of separate web pages, each one completely erasing the other when a link is selected.