WebReference:

"Sometimes content itself, not presentation or navigation, brings a subtle usability challenge. When page text is unavoidably long and complex, the mass of material can lead to confusion through a loss of context. Dense legal or technical documents are prone to this problem. One way to manage such text is to expose just what’s needed, hiding sections beneath expandable headings."

Just in case we decide to do this with some of our navigation options. Not sure it’s a good idea though. Will have to put thinking cap on.