How-To lessons, the Books page where you can find sources of online books to read, and the Web page, which lists a few good sites for homework help.
Breadcrumbs provide a visual indicator that a particular page has been visited.
Each word or word phrase will show you where you have come from and will list the section you are currently visiting. One other thing worth noting is that as you move further into the site the crumb trail changes to a darker gray color ending in black for the current page being viewed.