Comment tags
Comment tags are used for hiding information from display on the wiki. Simply enclose whatever you want to hide between "<!--" and "-->" , and it won't be displayed.
An example of how to use these follows this sentence. To see it, click the "edit" button, and you will see the phrase I have hidden by enclosing it between comment tags.
Comment tags are part of standard HTML and were created for, interestingly enough, comments. But they are also very useful for hiding unfinished items, or temporarily removing something from a page. The hidden material is referred to as being "commented out".