How to represent and visualize a lot of information at a glance is a hot topic in IT. A Treemap, also known as Heatmap, is an important tool for this. A TreeMap graphically represents a hierarchical structure. Typically, the hierarchy will involve a tree of nodes of different sizes and different colours.
A Heatmap/Treemap is great to see a lot of information in one glance. It can be interactive and allow you to drill down into some section of the hierarchy. More on treemapping on Wikipedia.