The WYSIWYG (pronounced wizzy-wig) is the editor built into Cascade in which you input and format page content. What You See Is What You Get. Behind the scenes it does the heavy-lifting and converts your content into the html necessary for display on the web. It’s likely the tool in Cascade that you interact with most frequently, but you might not know how to use all of the available features and buttons—special characters, images, tables, links and lists, as well as custom formats and styles.
Now there’s a section of the Cascade Help Pages that breaks down each button and feature—those that should be used and those that should not (for technical, design or usability reasons).