Hypertext is a way of creating links to other documents. A link to another place within the same document is called an anchor. These links themselves are 'invisible' to the user but they are indicated by a marked area within your current document. Typically you will see the marked area highlit in the colour blue. You can pursue the link by clicking on the highlight with the mouse. For example, pursue a link by clicking here.
You may have noticed that the link you just clicked on (yes, the one above this line of text !) has changed colour. This is simply to inform you, the user, of which links you have visited. Note that by default, unvisited links are blue and visited links are purple. It is however possible for people to change these default colours !
Click here to go to the tutorial overview