Via furrygoat.com. Look at this :
This is a hierarchical view of 10 blogs, with 154 total entries. It also shows the size of the entries and details on how recent the posts are. By using a "TreeMap" (first designed by Ben Shneiderman), huge amounts of hierarchical data can be shown in a small amount of space by representing items in nested rectangles. Adding size and color attributes adds to the level of detail that can be provided.
# Each RSS feed is it's own rectangle # The size of each "feed" rectangle is dependant on the number of entries in the feed # Each RSS entry is a separate box in the feed rectangle # The size of each RSS entry rectangle is directly determined by the length of the article # The color of each RSS entry is determined by how new it is. Entries that are newest are in yellow and gradient fills towards blue the older they get. For example, an item that is white might be about a week old, a yellow item could be only a day old, while a blue item is at least 2 weeks old