Not surprisingly, it's now an issue for large Web sites. Before Dynamic HTML, it was difficult to get users the information they need without losing their interest or losing them entirely in a labyrinth of links. In the days before Dynamic HTML, website builders used two approaches for developing navigation schemes, both of which ran the risk of frustrating users and adding to server load. Typically, website navigation schemes are decision trees - a throwback to the UNIX directory structure. The other approach uses a search engine to index the site's content.
Search engines are great for providing links to lots of content.
But the search function shouldn't replace a site's navigational structure - it should supplement it. By allowing users to navigate directly to web pages without loading all of the pages in between, these interactive navigation systems reduce server load and keep users happier. Built in layers and JavaScript 1.2, the navigation system also uses data files to store information on the states of the menu, reducing download time. Don't forget low-end browsers. Make sure you create an alternative navigation system.