On pages where a form needs to be filled in, the persistent navigation can sometimes be an unnecessary distraction. For instance, when I’m paying for my purchases on an e-commerce site, you don’t really want me to do anything but finish filling in the forms. The same is true when I’m registering, subscribing, giving feedback, or checking off personalization preferences. For these pages, it’s useful to have a minimal version of the persistent navigation with just the Site ID, a link to Home, and any Utilities that might help me fill out the form.