Basically, you have a “control panel” consisting of a number of categories, each with a checkbox. If you check the box, it displays things in that category. If you uncheck the box, those go away. A relatively simple concept. Drop in cookies so the site remembers your last show/hide settings to avoid annoying your visitors, e.g. “Every time I view the page, I see everything… even the stuff I turned off last time.”
View the source of the pages linked above.