Navigation elements help users find and move to areas of the site that have the desired information. They also help users to develop a mental model of the Web site. Use the right margin for the Web site's main index. Research shows that users click on topics in the right margin with much more efficiency than topics placed on the left because they are located much closer to the scroll bar. This allows users to quickly move the pointer between the scroll bar and the index items.
Benefits are particularly strong for laptops.