Here are some tutorials and references on how to implement expanding and collapsing divs. This are nice in that they collapse to make the page not too busy so as to information overload the viewer. Yet the viewer has to just make one click without a server page load to access the needed information.

Animated Expanding and Collapsing Divs

• Animated Collapsible Div 2.0 from DynamicDrive
• Animated Collapsible Panel in HTML
• Digg-style animated comment box shown Josh Davis here, Tamal White here, and Harry Maugans here
• Making Animated Collapsible Panel Using Javascript