when you have full keyboard access or something like that turned on in preferences, you can use the tab button to navigate to different parts in any program. if you press tab while it's highlighted like that you will see a little blue box go down the line of your book marks on the top of the screen there and eventually to every link on the page. it's a helpful feature for laptop users who don't want to have to deal with the little track pad thing and will get you around quite quickly in some apps, though web browsing is one of those things that was made for the mouse. i find the keyboard much more efficient than the mouse once you start to know some of the keyboard shortcuts, though a mouse is still necessary for some actions.